Acoustic output apparatus

ABSTRACT

The present disclosure discloses an acoustic output apparatus including at least one acoustic driver, a controller, and a supporting structure. The at least one acoustic driver may be configured to output sounds through at least two sound guiding holes. The at least two sound guiding holes may include a first sound guiding hole and a second sound guiding hole. The controller may be configured to control a phase and an amplitude of the sounds generated by the at least one acoustic driver using a control signal such that the sounds output by the at least one acoustic driver through the first and second sound guiding holes have opposite phases. The supporting structure may be provided with a baffle and configured to support the at least one acoustic driver such that the first and second sound guiding holes are located on both sides of the baffle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No.17/320,259, filed on May 14, 2021, which is a Continuation ofInternational Application No. PCT/CN2019/130942, filed on Dec. 31, 2019,which claims priority to Chinese Patent Application No. 201910364346.2filed on Apr. 30, 2019, and Chinese Patent Application No.201910888762.2 filed on Sep. 19, 2019, and Chinese Patent ApplicationNo. 201910888067.6 filed on Sep. 19, 2019, the contents of each of whichare hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to the field of acoustics, and moreparticularly, relates to an acoustic output apparatus.

BACKGROUND

An open-ear acoustic output apparatus is a portable acoustic outputapparatus that realizes sound conduction in a specific range. Comparedwith traditional in-ear and over-ear headphones, the open-ear acousticoutput apparatus has characteristics of not blocking or covering an earcanal, which may allow a user to obtain sound information in externalenvironment while listening to music, thereby improving the safety andcomfort level. Due to an open structure, a leaked sound of the open-earacoustic output apparatus is more serious than that of a traditionalearphone. Generally, two or more sound sources are used to construct aspecific sound field and adjust a sound pressure distribution to reducethe leaked sound, which can reduce the leaked sound to a certain extent,but there are still certain limitations. For example, a volume of thesound sent to the user may be reduced while the leaked sound issuppressed. In addition, because sounds at different frequencies havedifferent wavelengths, the suppression effect of the leaked sound athigh-frequency is not good.

Therefore, it is desirable to provide an acoustic output apparatus thatcan simultaneously increase a volume of the sound heard by the user andreduce the leaked sound.

SUMMARY

According to one aspect of the present disclosure, an acoustic outputapparatus is provided. The acoustic output apparatus may include atleast one acoustic driver configured to output sounds through at leasttwo sound guiding holes. The at least two sound guiding holes mayinclude a first sound guiding hole and a second sound guiding hole. Theacoustic output apparatus may include a controller configured to controla phase and an amplitude of the sounds generated by the at least oneacoustic driver using a control signal such that the sounds output bythe at least one acoustic driver through the first and second soundguiding holes have opposite phases. The acoustic output apparatus mayinclude a supporting structure provided with a baffle. The supportingstructure may be configured to support the at least one acoustic driversuch that the first and second sound guiding holes are located on bothsides of the baffle.

In some embodiments, the at least one acoustic driver may include avibration diaphragm. A first side of the vibration diaphragm in thesupporting structure may be provided with a first chamber fortransmitting sound. The first chamber may be acoustically coupled withthe first sound guiding hole. A second side of the vibration diaphragmin the supporting structure may be provided with a second chamber fortransmitting sound. The second chamber may be acoustically coupled withthe second sound guiding hole.

In some embodiments, a first acoustic route from the vibration diaphragmto the first sound guiding hole may be different from a second acousticroute from the vibration diaphragm to the second sound guiding hole.

In some embodiments, a ratio of a length of the first acoustic route toa length of the second acoustic route may be 0.5-2.

In some embodiments, the sounds output from the first and second soundguiding holes may have different sound pressure amplitudes.

In some embodiments, the at least one acoustic driver may include afirst acoustic driver and a second acoustic driver. The controller maybe configured to control the first acoustic driver to output a firstsound through the first sound guiding hole and the second acousticdriver to output a second sound from the second sound guiding hole. Thefirst sound and the second sound may have opposite phases.

In some embodiments, a first acoustic route from the first acousticdriver to the first sound guiding hole may be different from a secondacoustic route from the second acoustic driver to the second soundguiding hole.

In some embodiments, a ratio of the first acoustic route from the firstacoustic driver to the first sound guiding hole and the second acousticroute from the second acoustic driver to the second sound guiding holemay be 0.5-2.

In some embodiments, the first sound and the second sound may havedifferent sound pressure amplitudes.

In some embodiments, a distance between the first sound guiding hole andthe second sound guiding hole may be less than or equal to 12centimeters.

In some embodiments, the first sound guiding hole and a user's ear maybe located on one side of the baffle. The second sound guiding hole maybe located on the other side of the baffle. A length of an acousticroute from the first sound guiding hole to the user's ear may be lessthan a length of an acoustic route from the second sound guiding hole tothe user's ear.

In some embodiments, the first and second sound guiding holes may belocated on a same side of a user's ear. A ratio of a distance betweenthe user's ear and a sound guiding hole that is closer to the user's earamong the first and second sound guiding holes to a distance between thefirst and second sound guiding holes may be less than or equal to 3.

In some embodiments, the first and second sound guiding holes may belocated on a same side of a user's ear. A ratio of a distance betweenthe user's ear and a sound guiding hole that is closer to the user's earamong the first and second sound guiding holes to a distance between thefirst and second sound guiding holes may be less than or equal to 1.

In some embodiments, the first and second sound guiding holes may belocated on a same side of a user's ear. A ratio of a distance betweenthe user's ear and a sound guiding hole that is closer to the user's earamong the first and second sound guiding holes to a distance between thefirst and second sound guiding holes may be less than or equal to 0.9.

In some embodiments, a ratio of a distance between a center of thebaffle and a connection line between the first and second sound guidingholes to a height of the baffle may be less than or equal to 2.

In some embodiments, the at least two sound guiding holes may include athird sound guiding hole and a fourth sound guiding hole. A ratio of adistance between the third sound guiding hole and the baffle to adistance between the fourth sound guiding hole and the baffle may beless than or equal to ⅔.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is further illustrated in terms of exemplaryembodiments. These exemplary embodiments are described in detail withreference to the drawings.

These embodiments are not restrictive. In these embodiments, the samenumber represents the same structure, wherein:

FIG. 1 is a schematic diagram illustrating an exemplary structure of anacoustic output apparatus according to some embodiments of the presentdisclosure;

FIG. 2 is a schematic diagram illustrating an exemplary structure of anacoustic output apparatus according to some embodiments of the presentdisclosure;

FIG. 3 is a schematic diagram illustrating an exemplary structure of anacoustic output apparatus according to some embodiments of the presentdisclosure;

FIG. 4 is a schematic diagram illustrating two point sources accordingto some embodiments of the present disclosure;

FIG. 5 is a schematic diagram illustrating two point sources and alistening position according to some embodiments of the presentdisclosure;

FIG. 6 is a graph illustrating frequency response curves of two pointsources with different distances at a near-field listening positionaccording to some embodiments of the present disclosure;

FIG. 7 is a graph illustrating sound leakage indexes of two pointsources with different distances in a far field according to someembodiments of the present disclosure;

FIG. 8 is a schematic diagram illustrating an exemplary baffle providedbetween two point sources according to some embodiments of the presentdisclosure;

FIG. 9 is a graph illustrating frequency response curves of two pointsources in a near field when an auricle is located between the two pointsources according to some embodiments of the present disclosure;

FIG. 10 is a graph illustrating frequency response curves of two pointsources in a far field when an auricle is located between the two pointsources according to some embodiments of the present disclosure;

FIG. 11 is a graph illustrating sound leakage indexes of two pointsources when two point sources of an acoustic output apparatus aredistributed on both sides of an auricle according to some embodiments ofthe present disclosure;

FIG. 12 is a schematic diagram illustrating exemplary measurement mannerof sound leakage according to some embodiments of the presentdisclosure;

FIG. 13 is a graph illustrating frequency response curves of two pointsources with and without a baffle between two point sources according tosome embodiments of the present disclosure;

FIG. 14 is a graph illustrating frequency response curves of two pointsources in a near field when a distance d between the two point sourcesis 1 cm according to some embodiments of the present disclosure;

FIG. 15 is a graph illustrating frequency response curves of two pointsources in a near field when a distance d between the two point sourcesis 2 cm according to some embodiments of the present disclosure;

FIG. 16 is a graph illustrating frequency response curves of two pointsources in a near field when a distance d between the two point sourcesis 4 cm according to some embodiments of the present disclosure;

FIG. 17 is a graph illustrating sound leakage indexes of two pointsources in a far field when a distance d between the two point sourcesis 1 cm according to some embodiments of the present disclosure;

FIG. 18 is a graph illustrating sound leakage indexes of two pointsources in a far field when a distance d between the two point sourcesis 2 cm according to some embodiments of the present disclosure;

FIG. 19 is a graph illustrating sound leakage indexes of two pointsources in a far field when a distance d between the two point sourcesis 4 cm according to some embodiments of the present disclosure;

FIG. 20 is a graph illustrating exemplary distributions of differentlistening positions according to some embodiments of the presentdisclosure;

FIG. 21 is a graph illustrating frequency response curves of two pointsources without a baffle at different listening positions in a nearfield according to some embodiments of the present disclosure;

FIG. 22 is a graph illustrating sound leakage indexes of two pointsources without a baffle at different listening positions according tosome embodiments of the present disclosure;

FIG. 23 is a graph illustrating frequency response curves of two pointsources with a baffle at different listening positions in a near fieldaccording to some embodiments of the present disclosure;

FIG. 24 is a graph illustrating sound leakage indexes of two pointsources with a baffle at different listening positions according to someembodiments of the present disclosure;

FIG. 25 is a diagram illustrating an exemplary configuration of twopoint sources and a baffle according to some embodiments of the presentdisclosure;

FIG. 26 is a graph illustrating frequency response curves of two pointsources without a baffle or with baffles at different positions in anear field according to some embodiments of the present disclosure;

FIG. 27 is a graph illustrating frequency response curves of two pointsources without a baffle or with baffles at different positions in a farfield according to some embodiments of the present disclosure;

FIG. 28 is a graph illustrating sound leakage indexes of two pointsources without a baffle or with baffles at different positionsaccording to some embodiments of the present disclosure;

FIG. 29 is a graph illustrating near-field frequency response curves oftwo point sources without a baffle or with baffles of different heightsaccording to some embodiments in FIG. 25 ;

FIG. 30 is a graph illustrating far-field frequency response curves oftwo point sources without a baffle or with baffles of different heightsaccording to some embodiments in FIG. 25 ;

FIG. 31 is a graph illustrating sound leakage indexes of two pointsources without a baffle or with baffles of different heights accordingto some embodiments in FIG. 25 ;

FIG. 32 is a graph illustrating near-field frequency response curves oftwo point sources with different ratios of a distance between a centerof a baffle and a connection line between the two point sources to aheight of the baffle according to some embodiments in FIG. 25 ;

FIG. 33 is a graph illustrating far-field frequency response curves oftwo point sources with different ratios of a distance between a centerof a baffle and a connection line between the two point sources to aheight of the baffle according to some embodiments in FIG. 25 ;

FIG. 34 is a graph illustrating sound leakage indexes of two pointsources with different ratios of a distance between a center of a baffleand a connection line between the two point sources to a height of thebaffle according to some embodiments in FIG. 25 ;

FIG. 35 is a schematic diagram illustrating an exemplary structure of anacoustic output apparatus according to some embodiments of the presentdisclosure;

FIG. 36 is a schematic diagram illustrating a distribution of pointsources and baffles according to some embodiments of the presentdisclosure;

FIG. 37 is a graph illustrating near-field and far-field frequencyresponse curves of multi-point sources with and without baffles betweenmulti-point sources according to some embodiments in FIG. 36 ;

FIG. 38 is a graph illustrating sound leakage indexes of multi-pointsources with and without baffles between multi-point according to someembodiments in FIG. 36 ;

FIG. 39 is a graph illustrating sound leakage indexes of multi-pointsources corresponding to two distribution modes shown in (a) and (b) inFIG. 36 ;

FIG. 40 is a schematic diagram illustrating an exemplary structure of anacoustic output apparatus according to some embodiments of the presentdisclosure;

FIG. 41 is a schematic diagram illustrating sound leakage indexes underthe action of a combination of low-frequency two point sources andhigh-frequency two point sources according to some embodiments of thepresent disclosure; and

FIG. 42 is a schematic diagram illustrating a phone having sound guidingholes according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

In order to illustrate the technical solutions related to theembodiments of the present disclosure, a brief introduction of thedrawings referred to in the description of the embodiments is providedbelow. Obviously, the drawings described below are only some examples orembodiments of the present disclosure. Those having ordinary skills inthe art, without further creative efforts, may apply the presentdisclosure to other similar scenarios according to these drawings.Unless stated otherwise or obvious from the context, the same referencenumeral in the drawings refers to the same structure and operation.

It will be understood that the terms “system,” “device,” “unit,” and/or“module” are used herein to distinguish different components, elements,parts, sections, or assemblies of different levels. However, if otherexpressions may achieve the same purpose, the terms may be replaced bythe other expressions.

As used in the present disclosure and the appended claims, the singularforms “a,” “an,” and “the” include plural referents unless the contentclearly dictates otherwise. It will be further understood that the terms“comprises,” “comprising,” “includes,” and/or “including” when used inthe present disclosure, specify the presence of stated steps andelements, but do not preclude the presence or addition of one or moreother steps and elements.

According to some embodiments of the present disclosure, flow charts areused to illustrate the operations performed by the system. It is to beexpressly understood, the operations above or below may or may not beimplemented in order. Conversely, the operations may be performed ininverted order, or simultaneously. Besides, one or more other operationsmay be added to the flowcharts, or one or more operations may be omittedfrom the flowchart.

The present disclosure describes an acoustic output apparatus includingat least one acoustic driver. When a user wears the acoustic outputapparatus, the acoustic output apparatus may be at least located on aside of a head of the user, close to but not blocking ears of the user.The acoustic output apparatus may be worn on the head of the user (e.g.,non-ear open earphones that have the same or similar wearing style asglasses, headbands, or other structures) or other portions (e.g., aneck/shoulder area of the user) of a body of the user, or placed nearthe ears of the user by other manners (e.g., handheld by the user). Thesound generated by the at least one acoustic driver in the acousticoutput apparatus may be transmitted outwards through two sound guidingholes acoustically coupled with the at least one acoustic driver. Forexample, the two sound guiding holes may respectively transmit soundswith a same (or approximately same) amplitude and opposite (orapproximately opposite) phases outwards. In some embodiments, the twosound guiding holes may be distributed on both sides of a user'sauricle. In such cases, the user's auricle may be served as a baffle toseparate the two sound guiding holes, so that acoustic routes from thetwo sound guiding holes to the user's ear canal may be different. Insome embodiments, a baffle structure may be provided on the acousticoutput apparatus, so that the two sound guiding holes may berespectively located on both sides of the baffle, which may increase anacoustic distance difference of sounds transmitted from the two soundguiding holes to a user's ear (that is, a difference in sound distancesfrom the two sound guiding holes to the user's ear canal), therebyweakening the effect of sound cancellation, increasing a volume of soundheard by the user's ear (also referred to as near-field sound or heardsound), and providing the user with a better listening experience. Inaddition, the baffle may have little effect on sounds transmitted fromthe sound guiding holes to the environment (also referred to asfar-field sound). The far-field sounds generated by the two soundguiding holes may cancel each other, which may suppress the soundleakage of the acoustic output apparatus and prevent the sound generatedby the acoustic output apparatus from being heard by others near theuser.

FIG. 1 is a schematic diagram illustrating an exemplary structure of anacoustic output apparatus according to some embodiments of the presentdisclosure. As shown in FIG. 1 , the acoustic output apparatus 100 mayinclude a supporting structure 110, an acoustic driver 120, and acontroller (not shown in FIG. 1 ) disposed in the supporting structure110. In some embodiments, the acoustic output apparatus 100 may be wornon the user's body (for example, human body's head, neck, or uppertorso) through the supporting structure 110. At the same time, thesupporting structure 110 and the acoustic driver 120 may approach butnot block the ear canal, so that the user's ears may remain open, thusthe user may hear both the sound output from the acoustic outputapparatus 100 and the sound of the external environment. For example,the acoustic output apparatus 100 may be arranged around or partiallyaround the user's ear, and transmit sounds by means of air conduction orbone conduction.

The supporting structure 110 may be used to be worn on the user's bodyand include one or more acoustic drivers 120. In some embodiments, thesupporting structure 110 may have an enclosed shell structure with ahollow interior, and the one or more acoustic drivers 120 may be locatedinside the supporting structure 110. In some embodiments, the acousticoutput apparatus 100 may be combined with a product, such as glasses,headsets, head-mounted display devices, AR/VR helmets, etc. In thiscase, the supporting structure 110 may be fixed near the user's ear in ahanging or clamping manner. In some alternative embodiments, a hook maybe provided on the supporting structure 110, and the shape of the hookmay match the shape of the user's auricle, so that the acoustic outputapparatus 100 may be independently worn on the user's ear through thehook. The independently worn acoustic output apparatus 100 maycommunicate with a signal source (for example, a computer, a mobilephone, or other mobile devices) in a wired or wireless (for example,Bluetooth) manner. For example, the acoustic output apparatus 100 at theleft and right ears may be directly in communication connection with thesignal source in a wireless manner. As another example, the acousticoutput apparatus 100 at the left and right ears may include a firstoutput apparatus and a second output apparatus, the first outputapparatus may be in communication connection with the signal source, andthe second output apparatus may be connected with the first outputapparatus wirelessly. The audio output of the first output apparatus andthe second output apparatus may be synchronized through one or moresynchronization signals. A wireless connection disclosed herein mayinclude but not be limited to Bluetooth, a local area network, a widearea network, a wireless personal area network, a near fieldcommunication, or the like, or any combination thereof.

In some embodiments, the supporting structure 110 may be a shellstructure with a shape suitable for human ears, for example, a circularring shape, an oval shape, a polygonal shape (regular or irregular), a Ushape, a V shape, and a semi-circle, so that the supporting structure110 may be directly hooked at the user's ear. In some embodiments, thesupporting structure 110 may also include one or more fixed structures.The fixed structure(s) may include an ear hook, a head strip, or anelastic band, so that the acoustic output apparatus 100 may be betterfixed on the user, preventing the acoustic output apparatus fromfalling. Merely by way of example, the elastic band may be a headband tobe worn around the head region. As another example, the elastic band maybe a neckband to be worn around the neck/shoulder area. In someembodiments, the elastic band may be a continuous band and beelastically stretched to be worn on the user's head. In the meanwhile,the elastic band may also exert pressure on the user's head so that theacoustic output apparatus 100 may be fixed to a specific position of theuser's head. In some embodiments, the elastic band may be adiscontinuous band. For example, the elastic band may include a rigidportion and a flexible portion. The rigid portion may be made of a rigidmaterial (for example, plastic or metal), and the rigid portion may befixed to the supporting structure 110 of the acoustic output apparatus100 by a physical connection (for example, a clamping connection, athreaded connection, etc.). The flexible portion may be made of anelastic material (for example, cloth, composite material, or/andneoprene).

In some embodiments, when the user wears the acoustic output apparatus100, the supporting structure 110 may be located above or below theauricle. The supporting structure 110 may also be provided with a soundguiding hole 111 and a sound guiding hole 112 for transmitting sound. Insome embodiments, the sound guiding hole 111 and the sound guiding hole112 may be located on both sides of the user's auricle, respectively,and the acoustic driver 120 may output sounds through the sound guidinghole 111 and the sound guiding hole 112.

The acoustic driver 120 may be a component that can receive anelectrical signal, and convert the electrical signals into a soundsignal for output. In some embodiments, in terms of frequency, the typeof acoustic driver 120 may include an acoustic driver with alow-frequency (for example, 30 Hz-150 Hz), an acoustic driver with amid-low-frequency (for example, 150 Hz-500 Hz), an acoustic driver witha mid-high-frequency (for example, 500 Hz-5 kHz), an acoustic driverwith a high-frequency (for example, 5 kHz-16 kHz), or an acoustic driverwith a full-frequency (for example, 30 Hz-16 kHz), or the like, or anycombination thereof. Of course, the low frequency, high frequency, etc.mentioned herein may merely represent an approximate range of thefrequency, and different division manners may be used in differentapplication scenarios. For example, a frequency division point may bedetermined. Low frequency may represent a frequency range below thefrequency division point, and high frequency may represent a frequencyrange above the frequency division point. The frequency division pointmay be an arbitrary value within the audible range of the human ear, forexample, 500 Hz, 600 Hz, 700 Hz, 800 Hz, 1000 Hz, etc. In someembodiments, in terms of a principle, the acoustic driver 120 mayinclude but is not limited to a moving coil driver, a moving irondriver, a piezoelectric driver, an electrostatic driver, amagnetostrictive driver, or the like.

In some embodiments, the acoustic driver 120 may include a vibrationdiaphragm. When the vibration diaphragm vibrates, sound may betransmitted from the front and rear sides of the vibration diaphragm,respectively. In some embodiments, the front side of the vibrationdiaphragm in the supporting structure 110 may be provided with a frontchamber 113 for transmitting sound. The front chamber 113 may beacoustically coupled with the sound guiding hole 111, and the sound onthe front side of the vibration diaphragm may be outputted from thesound guiding hole 111 through the front chamber 113. The rear side ofthe vibration diaphragm in the supporting structure 110 may be providedwith a rear chamber 114 for transmitting sound. The rear chamber 114 maybe acoustically coupled with the sound guiding hole 112, and the soundon the rear side of the vibration diaphragm may be outputted from thesound guiding hole 112 through the rear chamber 114. It should be notedthat, when the vibration diaphragm is vibrating, the front side and therear side of the vibration diaphragm may simultaneously generate soundswith opposite phases. After passing through the front chamber 113 andthe rear chamber 114, respectively, the sounds may propagate outwardfrom the positions of the sound guiding hole 111 and the sound guidinghole 112, respectively. In some embodiments, by adjusting the structureof the front chamber 113 and the rear chamber 114, the sounds output bythe acoustic driver 120 at the sound guiding hole 111 and the soundguiding hole 112 may meet specific conditions. For example, by designingthe lengths of the front chamber 113 and the rear chamber 114, the soundguiding hole 111 and the sound guiding hole 112 may output sounds with aspecific phase relationship (for example, opposite phases). Therefore,the problems including a small volume of the sound heard by the user inthe near field of the acoustic output apparatus 100 and a large soundleakage in the far field of the acoustic output apparatus 100 may beeffectively resolved.

In some alternative embodiments, the acoustic driver 120 may alsoinclude a plurality of vibration diaphragms (for example, two vibrationdiaphragms). Each of the plurality of vibration diaphragms may vibraterespectively to generate sounds, which may respectively pass throughdifferent cavities connected to the vibration diaphragms in thesupporting structure, and output from corresponding sound guiding holes.The plurality of vibration diaphragms may be controlled by the samecontroller or different controllers and generate sounds that meetcertain phase and amplitude conditions (for example, sounds with thesame amplitude but opposite phases, sounds with different amplitudes andopposite phases, etc.).

The controller may be used to control a phase and an amplitude of asound generated by the acoustic driver 112. In some embodiments, a countof controllers in the acoustic output apparatus 100 may be one or more.For example, when the acoustic output apparatus 100 includes a pluralityof acoustic drivers 112, the count of controllers may be one. Thecontroller may control, using a control signal, the plurality ofacoustic drivers simultaneously 112 to generate sounds that meet acertain phase and amplitude condition. As another example, the count ofcontrollers in the acoustic output apparatus 100 may be equal to thecount of acoustic drivers. Each controller may control an acousticdriver corresponding to the controller to generate a sound that meetsthe certain phase and amplitude condition.

In order to further explain the specific structure of the acousticoutput apparatus 100, the present disclosure takes an acoustic outputapparatus including two acoustic drivers as an example. As shown in FIG.2 , an acoustic output apparatus 200 may include a supporting structure210, a first acoustic driver 221, a second acoustic driver 222, and acontroller (not shown in FIG. 2 ). The supporting structure 110 may beprovided with a sound guiding hole 211 and a sound guiding hole 212 foroutputting sound. The first acoustic driver 221, the second acousticdriver 222, and the controller may be disposed inside the supportingstructure 210. The controller may control the first acoustic driver 221and the second acoustic driver 222 to generate sounds that meet thecertain phase and amplitude condition (for example, sounds with a sameamplitude but opposite phases, sounds with different amplitudes andopposite phases, etc.) using a control signal. In some embodiments, thesound guiding hole 211 and the sound guiding hole 212 may be located onboth sides of the user's auricle. The first acoustic driver 221 mayoutput sound through the sound guiding hole 211, and the second acousticdriver 221 may output sound through the sound guiding hole 212.

In some embodiments, a cavity 213 for transmitting sound may be providedbetween the first acoustic driver 221 and the sound guiding hole 211 inthe supporting structure 210. The sound generated by the first acousticdriver 211 may be transmitted through the cavity 213 and outputted fromthe sound guiding hole 211. A cavity 214 for transmitting sound may beprovided between the second acoustic driver 222 and the sound guidinghole 212 in the supporting structure 210. The sound generated by thesecond acoustic driver 222 may be transmitted through the cavity 214 andoutputted from the sound guiding hole 212. In some embodiments, thecontroller may control the first acoustic driver 221 and the secondacoustic driver 222 to simultaneously generate a set of sounds withopposite phases by a control signal. For example, if the first acousticdriver 221 and the second acoustic driver 222 have the same frequencyresponse characteristic, the controller may adjust electrical signalsinput into the first acoustic driver 221 and the second acoustic driver222 by the control signal, so that the electrical signals have oppositephases. Further, driven by the electrical signals with opposite phases,the first acoustic driver 221 and the second acoustic driver 222 maygenerate sounds with opposite phases. After passing through the cavity213 and the cavity 214 respectively, the sounds may propagate outwardfrom the sound guiding hole 211 and the sound guiding hole 212,respectively. In some embodiments, the structures of the cavity 213 andthe cavity 214 may be specially designed so that the sound output by thefirst acoustic driver 221 from the sound guiding hole 211 and the soundoutput by the second acoustic driver 222 from the sound guiding hole 212meet a specific condition. For example, the lengths of the cavity 213and the cavity 214 may be designed so that the sounds with oppositephases may be output from the sound guiding hole 211 and the soundguiding hole 212. In some embodiments, the controller may control thefirst acoustic driver 221 and the second acoustic driver 222 tosimultaneously generate sounds with a same amplitude by the controlsignal. For example, if the first acoustic driver 221 and the secondacoustic driver 222 have the same frequency response characteristic, thecontroller may adjust the electrical signals input into the firstacoustic driver 221 and the second acoustic driver 222 by the controlsignal. The electrical signals may control output powers of the firstacoustic driver 221 and the second acoustic driver 222, respectively, sothat the two electrical signals have a same amplitude. Further, drivenby the electrical signals with the same amplitude, the first acousticdriver 221 and the second acoustic driver 222 may generate sounds with asame amplitude. It should be noted that the controller is not limited tocontrolling the first acoustic driver 221 and the second acoustic driver222 to generate the sounds with the same amplitude and opposite phasesby the control signal. For example, in some embodiments, the controllermay control the first acoustic driver 221 and the second acoustic driver222 to generate sounds with a same amplitude and a same phase by acontrol signal different from the above-mentioned control signal. Asanother example, in some embodiments, the controller may control thefirst acoustic driver 221 and the second acoustic driver 222 to generatesounds with different amplitudes and different phases by a controlsignal different from the above-mentioned control signal. The controllermay also control the amplitude and the phase of sounds generated byacoustic drivers other than the first acoustic driver 221 and the secondacoustic driver 222, which may not be limited and can be adjustedaccording to specific requirements.

The two sound guiding holes of the acoustic output apparatus 200 may bedistributed on both sides of a user's auricle, which may increase avolume of the sound heard by the user's ear (also referred to asnear-field sound) and suppress the sound leakage of the acoustic outputapparatus 200 to a certain extent. In some embodiments, the two soundguiding holes of the acoustic output apparatus 200 may be divided by abaffle, which may achieve effects of increasing the near-field sound andreducing the far-field leakage. FIG. 3 is a schematic diagramillustrating an exemplary structure of an acoustic output apparatusaccording to some embodiments of the present disclosure. As shown inFIG. 3 , the acoustic output apparatus 300 may include a supportingstructure 310, an acoustic driver 320, a baffle 330, and a controller.The acoustic driver 320 and the controller may be located inside thesupporting structure 310. In some embodiments, the supporting structure310 may also be provided with a sound guiding hole 311 and a soundguiding hole 312 for transmitting sound. The sound guiding hole 311 andthe sound guiding hole 312 may be located on a front side or a rear sideof the user's auricle. A volume of a sound of the acoustic outputapparatus 300 at any point in the space may be related to a distancefrom the point to the sound guiding hole 311 and the sound guiding hole312. Merely by way of example, as shown in FIG. 3 , the sound guidinghole 311 and the sound guiding hole 312 may respectively output soundswith the same amplitude and opposite phases, (represented by symbols “+”and “−”, respectively). In such cases, when the distance from the pointin the space to the sound guiding hole 311 is equal to the distance fromthe point in the space to the sound guiding hole 312, a volume of asound at the point may be relatively small s according to the principleof interference cancellation. When the distance from the point in thespace to the sound guiding hole 311 is not equal to the distance fromthe point in the space to the sound guiding hole 312, the greaterdifference between the two distances, the greater the volume of thesound at the point.

The baffle 330 may be configured to adjust acoustic distances from thesound guiding hole 311 and the sound guiding hole 312 to the user's ear(i.e., a listening position). As shown in FIG. 3 , the sound guidinghole 311 and the sound guiding hole 312 may be located on both sides ofthe baffle 330, respectively. A count of the baffle 330 may be one ormore. For example, one or more baffles 330 may be provided between thesound guiding hole 311 and the sound guiding hole 312. As anotherexample, when the acoustic output apparatus 300 further includes soundguiding hole(s) other than the sound guiding hole 311 and the soundguiding hole 312, one or more baffles 330 may be provided between everytwo sound guiding holes. In some embodiments, the baffle 330 may befixedly connected to the supporting structure 310. For example, thebaffle 330 may be a part of the supporting structure 310 or integrallyformed with the supporting structure 310. In other embodiments, thebaffle 330 may be connected with other components (for example, an outershell of the acoustic output apparatus 300) of the acoustic outputapparatus 300.

In some embodiments, the acoustic driver 320 may include a vibrationdiaphragm. When the vibration diaphragm vibrates, sounds may betransmitted from the front and rear sides of the vibration diaphragm,respectively. In some embodiments, the front side of the vibrationdiaphragm in the supporting structure 310 may be provided with a frontchamber 313 for transmitting sound. The front chamber 313 may beacoustically coupled with the sound guiding hole 311, and the sound onthe front side of the vibration diaphragm may be outputted from thesound guiding hole 311 through the front chamber 313. The rear side ofthe vibration diaphragm in the supporting structure 310 may be providedwith a rear chamber 314 for transmitting sound. The rear chamber 314 maybe acoustically coupled with the sound guiding hole 312, and the soundon the rear side of the vibration diaphragm may be outputted from thesound guiding hole 112 through the rear chamber 114. It should be notedthat, when the vibration diaphragm is vibrating, the front and rearsides of the vibration diaphragm may simultaneously generate sounds withopposite phases. After passing through the front chamber 313 and therear chamber 314, respectively, the sounds may respectively propagateoutward from the sound guiding hole 311 and the sound guiding hole 312.The supporting structure 310, the acoustic driver 320, the controller,the front chamber 313, and the rear chamber 314 in the acoustic outputapparatus 300 may be similar to their respective correspondingcomponents in FIG. 1 , which may not be repeated herein.

It should be noted that the above descriptions are only for convenienceof description, and are not intended to limit the present disclosure. Itmay be understood that for those skilled in the art, after understandingthe principle of the present disclosure, various modifications andchanges in form and details of the acoustic output apparatus may be madewithout departing from this principle. For example, a count of acousticdrivers in an acoustic output apparatus may not be limited to two inFIG. 2 . The count of acoustic drivers may be three, four, five, etc.The supporting structure may be adjusted according to the count anddistribution of the acoustic driver(s) in the acoustic output apparatus.As another example, an acoustic driver and a sound guiding hole may beacoustically coupled through a sound guiding tube. These changes are allwithin the protection scope of the present disclosure.

In order to further illustrate the influence of the distribution of thesound guiding holes on the user's auricle or both sides of the baffle onthe sound output effect of the acoustic output apparatus, in the presentdisclosure, the acoustic output apparatus and the user's auricle may beequivalent to a model including two point sources and the baffle.

Just for the convenience of description and for the purpose ofillustration, when sizes of the sound guiding hole on the acousticoutput apparatus are small, each sound guiding hole can be approximatelyregarded as a point source. The sound field sound pressure p generatedby a single point source may satisfy the Equation (1):

$\begin{matrix}{{p = {\frac{j\omega\rho_{0}}{4\pi r}Q_{0}\exp j\left( {{\omega t} - {kr}} \right)}},} & (1)\end{matrix}$

where ω denotes an angular frequency, ρ₀ denotes an air density, rdenotes a distance between a target point and the point source, Q₀denotes a volume velocity of the point source, and k denotes the wavenumber. The magnitude of the sound field pressure of the point source atthe target point is inversely proportional to the distance from thetarget point to the point source.

Two sound guiding holes (for example, the sound guiding hole 111 and thesound guiding hole 112) may be set on the acoustic output apparatus. Inthis case, two point sources may be formed, which may reduce soundtransmitted from the acoustic output apparatus to the surroundingenvironment (i.e., far-field sound leakage). In some embodiments, thesounds output from two sound guiding holes, that is, two point sourcesmay have a certain phase difference. When the distance and the phasedifference between the two point sources meet a certain condition, theacoustic output apparatus may output different sound effects in the nearfield and the far field. For example, if the phases of the two pointsources corresponding to the two sound guiding holes are opposite, thatis, an absolute value of the phase difference between the two pointsources is 180 degrees, the far-field leakage (also referred to asfar-field sound leakage) may be reduced according to the principle ofreversed phase sound cancellation.

As shown in FIG. 4 , a sound field sound pressure p generated by twopoint sources may satisfy Equation (2):

$\begin{matrix}{{p = {{\frac{A_{1}}{r_{1}}\exp j\left( {{\omega t} - {kr_{1}} + \varphi_{1}} \right)} + {\frac{A_{2}}{r_{2}}\exp j\left( {{\omega t} - {kr_{2}} + \varphi_{2}} \right)}}},} & (2)\end{matrix}$

where A₁ and A₂ denote intensities of the two point sources, φ₁ and φ₂denote phases of the two point sources, respectively, d denotes adistance between the two point sources, and r₁ and r₂ may satisfy theEquation (3):

$\begin{matrix}\left\{ {\begin{matrix}{r_{1} = \sqrt{r^{2} + \left( \frac{d}{2} \right)^{2} - {2*r*\frac{d}{2}*\cos\theta}}} \\{r_{2} = \sqrt{r^{2} + \left( \frac{d}{2} \right)^{2} + {2*r*\frac{d}{2}*\cos\theta}}}\end{matrix},} \right. & (3)\end{matrix}$

where r denotes a distance between a target point and the center of thetwo point sources in the space, and θ indicates an angle between a lineconnecting the target point and the center of the two point sources andthe line on which the two point source is located.

It may be concluded from Equation (3) that a magnitude of the soundpressure p of the target point in the sound field may relate to theintensity of each point source, the distance d, the phase of each pointsource, and the distance r.

FIG. 5 is a schematic diagram illustrating two point sources and alistening position according to some embodiments of the presentdisclosure. FIG. 6 is a graph illustrating frequency response curves oftwo point sources with different distances at a near-field listeningposition according to some embodiments of the present disclosure. Insome embodiments, the listening position may be taken as a target pointto further illustrate a relationship between a sound pressure at thetarget point and the distance d between the two point sources. As usedherein, the listening position may be used to indicate a position of theuser's ear. The sound at the listening position may be used to representthe near-field sound generated by two point sources. It should be notedthat “near-field sound” may refer to a sound within a certain range froma sound source (for example, the point source equivalent to the soundguiding hole 111), for example, a sound within 0.2 m from the soundsource. Merely by way of example, as shown in FIG. 5 , a point source A₁and a point source A₂ may be on a same side of the listening position,the point source A₁ may be closer to the listening position, and thepoint source A₁ and the point source A₂ may output sounds with the sameamplitude but opposite phases, respectively. As shown in FIG. 6 , as thedistance between the point source A₁ and the point source A₂ graduallyincreases (for example, from d to 10 d), the sound volume at thelistening position may gradually increase. That is, as the distancebetween the point source A₁ and the point source A₂ increases, thedifference in sound pressure amplitude (i.e., sound pressure difference)between the two sounds reaching the listening position may becomelarger, making the sound cancellation effect weaker, which may increasethe sound volume at the listening position. However, due to theexistence of sound cancellation, the sound volume at the listeningposition may still be less than the sound volume generated by a singlepoint source at a same position in the low and middle frequency band(for example, a frequency of less than 1000 Hz). However, in thehigh-frequency band (for example, a frequency close to 10000 Hz), due tothe decrease in the wavelength of the sound, mutual enhancement of thesound may appear, making the sound generated by the two point sourceslouder than that of the single point source. In some embodiments, asound pressure may refer to the pressure generated by the sound throughthe vibration of the air.

In some embodiments, by increasing the distance between the two pointsources (for example, the point source A₁ and the point source A₂), thesound volume at the listening position may be increased. But as thedistance increases, the sound cancellation of the two point sources maybecome weaker, which may lead to an increase of the far-field soundleakage. For illustration purposes, FIG. 7 is a graph illustrating soundleakage indexes (also referred to as normalization parameters) of twopoint sources with different distances in a far field according to someembodiments of the present disclosure. As shown in FIG. 7 , a far-fieldsound leakage index of a single point source may be taken as areference, as the distance between two point sources increases from d to10d, the far-field sound leakage index may gradually increase, whichindicates that the sound leakage becomes larger. More descriptionsregarding the sound leakage index may be found in equation (4) andrelated descriptions.

In some embodiments, adding a baffle structure to the acoustic outputapparatus may be beneficial to improve the output effect of the acousticoutput apparatus, that is, to increase the sound intensity at thenear-field listening position, while reducing the volume of thefar-field sound leakage. For illustration, FIG. 8 is a schematic diagramillustrating an exemplary baffle provided between two point sourcesaccording to some embodiments of the present disclosure. As shown inFIG. 8 , when a baffle is provided between the point source A₁ and thepoint source A₂, in the near field, the sound wave of the point sourceA₂ may need to bypass the baffle to interfere with the sound wave of thepoint source A₁ at the listening position, which may be equivalent toincreasing the length of the acoustic route from the point source A₂ tothe listening position. Therefore, assuming that the point source A₁ andthe point source A₂ have a same amplitude, compared to the case withouta baffle, the difference in the amplitude of the sound waves of thepoint source A₁ and the point source A₂ at the listening position mayincrease, so that the degree of cancellation of the two sounds at thelistening position may decrease, causing the sound volume at thelistening position to increase. In the far field, because the soundwaves generated by the point source A₁ and the point source A₂ do notneed to bypass the baffle in a large space, the sound waves mayinterfere (similar to the case without a baffle). Compared to the casewithout a baffle, the sound leakage in the far field may not increasesignificantly. Therefore, a baffle structure being provided between thepoint source A₁ and the point source A₂ may increase the sound volume atthe near-field listening position significantly while the volume of thefar-field leakage does not increase significantly.

FIG. 9 is a graph illustrating frequency response curves of two pointsources in a near field when an auricle is located between the two pointsources according to some embodiments of the present disclosure. FIG. 10is a graph illustrating frequency response curves of two point sourcesin a far field when an auricle is located between the two point sourcesaccording to some embodiments of the present disclosure. In the presentdisclosure, when the two point sources are located on both sides of theauricle, the auricle may serve as a baffle, so the auricle may also bereferred to as a baffle for convenience. As an example, due to theexistence of the auricle, the result may be equivalent to that thenear-field sound may be generated by two point sources with a distanceof D₁ (also known as mode 1). The far-field sound may be generated bytwo point sources with a distance of D₂ (also known as mode 2), D₁>D₂.As shown in FIG. 9 , in a low-frequency range (e.g., when the frequencyis less than 1000 Hz), when the two point sources are distributed onboth sides of the auricle, the volume at the near-field sound (i.e., thesound heard by the user's ear) may basically be the same as that of thenear-field sound in mode 1, be greater than the volume of the near-fieldsound in mode 2 and be close to the volume of the near-field sound of asingle point source. As the frequency increases (e.g., when thefrequency is between 2000 Hz-7000 Hz), the volume of the near-fieldsound in mode 1 and the two point sources being distributed on bothsides of the auricle may be greater than that of the single pointsource. It shows that when the user's auricle is located between the twopoint sources, the volume of the near-field sound transmitted from thesound source to the user's ear may be effectively enhanced. As shown inFIG. 10 , as the frequency increases, the volume of the far-fieldleakage may increase, but when the two point sources are distributed onboth sides of the auricle, the volume of the far-field leakage generatedby the two point sources may be basically the same as that of the volumeof the far-field leakage in mode 2, and both of which may be less thanthe volume of the far-field leakage in mode 1 and the volume of thefar-field leakage of a single point source. It shows that when theuser's auricle is located between the two point sources, the soundtransmitted from the sound source to the far field may be effectivelyreduced, that is, the sound leakage from the sound source to thesurrounding environment may be effectively reduced.

More descriptions regarding the specific meaning and related content ofthe sound leakage index may refer to the following description. In theapplication of the open acoustic output apparatus, it may be necessaryto ensure that a sound pressure P_(ear) at the listening position islarge enough to meet the listening needs. Meanwhile, it may be necessaryto ensure that a sound pressure P_(far) at the far field is small enoughto reduce sound leakage. Therefore, the sound leakage index α may beused as an index to evaluate the ability to reduce the sound leakage.

$\begin{matrix}{\alpha = {\frac{{❘P_{far}❘}^{2}}{{❘P_{ear}❘}^{2}}.}} & (4)\end{matrix}$

It may be concluded from Equation (4) that, the smaller the soundleakage index is, the stronger the ability of the acoustic outputapparatus to reduce the sound leakage may be. When the volume of thenear-field sound at the listening position remains unchanged, thesmaller the sound leakage index is, the smaller the far-field soundleakage may be. As shown in FIG. 11 , when the frequency is less than10000 Hz, the leakage index of the two point sources being distributedon both sides of the auricle may be less than the leakage index in thecase of mode 1 (no baffle structure between the two point sources, andthe distance is D₁), Mode 2 (no baffle structure between the two pointsources, and the distance is D₂) and the single point source, which mayalso show that when the two point sources are located on both sides ofthe auricle, the acoustic output apparatus may have a better capabilityto reduce the sound leakage.

FIG. 12 is a schematic diagram illustrating exemplary measurement mannerof sound leakage according to some embodiments of the presentdisclosure. As shown in FIG. 12 , a listening position may be located ona left side of a point source A₁. A measurement manner of the leakagesound may be that a plurality of points on a spherical surface centeredby a center point of the two point sources (for example, A₁ and A₂ inFIG. 7 ) with a radius of r may be identified, and an average value ofamplitudes of the sound pressure at the plurality of points may bedetermined as a value of the sound leakage. It should be noted that themeasurement manner of the leakage sound may merely serve as an exemplaryillustration, which may be not limited. The manner for measuring anddetermining the sound leakage may be adjusted according to the actualconditions. For example, one or more points in the far field may betaken as the position for measuring the sound leakage. As anotherexample, a center of the two point sources may be used as a center of acircle at the far field, and sound pressure amplitudes of two or morepoints evenly distributed at the circle according to a certain spatialangle may be averaged as the value of the sound leakage. In someembodiments, a measurement manner of the sound heard by the user may bethat a location point near the point source may be identified as alistening position, and an amplitude of the sound pressure measured atthe listening position may be determined as a volume of the sound heardby the user. In some embodiments, the listening position may be on theconnection line between two point sources or not on the connection linebetween two point sources. The manner for measuring and determining thevolume of the sound heard by the user may be adjusted according to theactual conditions. For example, the sound pressure amplitudes of otherpoints or one or more points in the near field may be averaged as thevolume of the sound heard by the user. As another example, a certainpoint source may be used as a center of a circle at the near field, andthe sound pressure amplitudes of two or more points evenly distributedat the circle according to a certain spatial angle may be averaged asthe volume of the sound heard by the user. In some embodiments, adistance between the near-field listening position and a point sourcemay be far less than a distance between the point source and thespherical surface for measuring the far-field sound leakage.

It should be noted that the sound guiding holes for outputting sound aspoint sources may merely serve as an illustration of the principle andeffect in the present disclosure, and may not limit the shapes and sizesof the sound guiding holes in practical applications. In someembodiments, if an area of a sound guiding hole is large, the soundguiding hole may also be equivalent to a surface source radiating soundoutward. In some embodiments, the point source may also be realized byother structures, such as a vibration surface, a sound radiationsurface, etc. For those skilled in the art, without creative activities,it may be known that the sound generated by structures such as a soundguiding hole, a vibration surface, a sound radiation surface, or thelike may be equivalent to a point source at the spatial scale discussedin the present disclosure, and may have the same sound propagationcharacteristics and the same mathematical description. Further, forthose skilled in the art, without creative activities, it may be knownthat the acoustic effect achieved by “an acoustic driver may outputtingsound from at least two first sound guiding holes” described in thepresent disclosure may also achieve the same effect by other acousticstructures, for example, “at least two acoustic drivers each may outputsound from at least one sound radiation surface”. According to actualconditions, other acoustic structures may be selected for adjustment andcombination, and the same acoustic output effect may also be achieved.The principle of radiating sound outward with structures such as surfacesources may be similar to that of point sources, which may not berepeated here. Further, a count of sound guiding holes (point source orsurface source) on the acoustic output apparatus may not be limited totwo, which may be three, four, five, etc., thereby forming a pluralityof sets of two point/surface sources or a set of multi-point/surfacesources, which may not be limited herein and may achieve the technicaleffects that can be achieved by the two point sources in the presentdisclosure.

In order to further explain the effect on the sound output effect withor without a baffle between the two point sources or the two soundguiding holes, the volume of the near-field sound at the listeningposition or/and the volume of the far-field leakage under differentconditions may be specifically described below.

FIG. 13 is a graph illustrating frequency response curves of two pointsources with and without a baffle between two point sources according tosome embodiments of the present disclosure. As shown in FIG. 13 , afteradding a baffle between the two point sources (that is, two soundguiding holes) of the acoustic output apparatus, in the near field, itmay be equivalent to increasing the distance between the two pointsources, and the volume at the near-field listening position may beequivalent to being generated by a set of two point sources with alarger distance. The volume of the near-field sound may be significantlyincreased compared to the case without a baffle. In the far field, sincethe interference of the sound waves generated by the two point sourcesis rarely affected by the baffle, the sound leakage may not changesignificantly with or without the baffle. It may be seen that by settinga baffle between the two sound guiding holes (two point sources), thecapability to reduce sound leakage of the acoustic output apparatus maybe effectively improved, the volume of the near-field sound of theacoustic output apparatus may be significantly increased. Therefore, therequirements for sound generation components of the acoustic outputapparatus may be greatly reduced, which may reduce the electrical lossof the acoustic output apparatus at the same time due to simple circuitstructure, so that the working time of the acoustic output apparatus maybe greatly prolonged under a certain amount of electricity.

FIG. 14 is a graph illustrating frequency response curves of two pointsources in a near field when a distance d between the two point sourcesis 1 cm according to some embodiments of the present disclosure. FIG. 15is a graph illustrating frequency response curves of two point sourcesin a near field when a distance d between the two point sources is 2 cmaccording to some embodiments of the present disclosure. FIG. 16 is agraph illustrating frequency response curves of two point sources in anear field when a distance d between the two point sources is 4 cmaccording to some embodiments of the present disclosure. FIG. 17 is agraph illustrating sound leakage indexes of two point sources in a farfield when a distance d between the two point sources is 1 cm accordingto some embodiments of the present disclosure. FIG. 18 is a graphillustrating sound leakage indexes of two point sources in a far fieldwhen a distance d between the two point sources is 2 cm according tosome embodiments of the present disclosure. FIG. 19 is a graphillustrating sound leakage indexes of two point sources in a far fieldwhen a distance d between the two point sources is 4 cm according tosome embodiments of the present disclosure. As shown in FIGS. 14-16 ,for the different distances d (e.g., 1 cm, 2 cm, 4 cm) of differentsound guiding holes, at a certain frequency, in the near-field listeningposition (e.g., the user's ears), the sound volume of two sound guidingholes located on both sides of the auricle, (i.e., the “baffle function”situation shown in the figure) may be greater than the sound volume oftwo sound guiding holes located on a same side of the auricle (i.e., thecase of “without baffle” as shown in the figure). The certain frequencymentioned here may be below 10000 Hz, or preferably, below 5000 Hz, ormore preferably, below 1000 Hz.

As shown in FIGS. 17-19 , for the different distanced (for example, 1cm, 2 cm, 4 cm) of the sound guiding holes, at a certain frequency, inthe far-field position (e.g., the environmental position far away fromthe user's ears), the volume of the leakage sound generated when the twosound guiding holes are located on both sides of the auricle may besmaller than that generated when the two sound guiding holes are notlocated on both sides of the auricle. It should be noted that as thedistance between two sound guiding holes or two point sources increases,the interference cancellation of sound at the far-field position may beweakened, leading to a gradual increase in the far-field leakage and aweaker ability to reduce sound leakage. Therefore, the distance dbetween two sound guiding holes or the two point sources may not be toolarge. In some embodiments, in order to keep the sound output deviceoutput sound as loud as possible in the near field and suppress thesound leakage in the far field, the distance d between the two soundguiding holes may be set to no more than 20 cm. Preferably, the distanced between the two sound guiding holes may be no more than 12 cm. Morepreferably, the distance d between the two sound guiding holes may be nomore than 10 cm. More preferably, the distance d between the two soundguiding holes may be no more than 8 cm. More preferably, the distance dbetween the two sound guiding holes may be no more than 6 cm. Morepreferably, the distance d between the two sound guiding holes may be nomore than 3 cm.

In some embodiments, on the premise of maintaining the distance betweenthe two point sources, a relative position of the listening position tothe two point sources may have a certain effect on the volume of thenear-field sound and the far-field leakage reduction. In order toimprove the acoustic output effect of the acoustic output apparatus, insome embodiments, the acoustic output apparatus may be provided with atleast two sound guiding holes, the at least two sound guiding holes mayinclude two sound guiding holes located on the front and rear sides ofthe user's auricle, respectively. In some specific embodiments,considering that the sound propagated from the sound guiding holelocated on the rear side of the user's auricle needs to bypass over theauricle to reach the user's ear canal, the acoustic route between thesound guiding hole located on the front side of the auricle and theuser's ear canal (i.e., the acoustic distance from the sound guidinghole to the of the entrance) may be shorter than the acoustic routebetween the sound guiding hole located on the rear side of the auriclefrom the user's ear. In some embodiments, the acoustic output apparatusmay include two sound guiding holes. The two sound guiding holes may berespectively located on both sides of the listening position, and thebaffle may be located at one side of the listening position. Thedistance from one sound guiding hole on a same side of the baffle as thelistening position of the two sound guiding holes to the listeningposition may be shorter than the distance from the other sound guidinghole to the listening position. In order to further illustrate theeffect of the listening position on the sound output effect, as anexemplary illustration, as shown in FIG. 20 , four representativelistening positions (a listening position 1, a listening position 2, alistening position 3, a listening position 4) may be selected toillustrate the effect and principle of listening position selection. Thelistening position 1, the listening position 2, and the listeningposition 3 may have an equal distance from the point source A₁, whichmay be r₁. The distance between the listening position 4 and the pointsource A₁ may be r₂, and r₂<r₁. The point source A1 and the point sourceA2 may generate sounds with opposite phases, respectively.

FIG. 21 is a graph illustrating frequency response curves of two pointsources without a baffle at different listening positions in a nearfield according to some embodiments of the present disclosure. FIG. 22is a graph illustrating sound leakage indexes at different listeningpositions obtained based on Equation (4) on the basis of FIG. 21 . Asshown in FIGS. 21 and 22 , for the listening position 1, since theacoustic route difference between the point source A₁ and the pointsource A₂ to the listening position 1 is small, the difference inamplitude of the sound generated by the two point sources at thelistening position 1 may be small, so that interference of the sounds oftwo point sources at the listening position 1 may cause the volume ofthe sound heard by the user to be smaller than that of other listeningpositions. For the listening position 2, compared with the listeningposition 1, the distance between the listening position 2 and the pointsource A₁ may remain unchanged, that is, the acoustic route from thepoint source A₁ to the listening position 2 may not change. However, thedistance between the listening position 2 and the point source A₂ may belonger, and the acoustic route between the point source A₂ and thelistening position 2 may increase. The amplitude difference between thesound generated by the point source A₁ and the point source A₂ at thelistening position 2 may increase, so the volume of the soundtransmitted from the two point sources after interference at listeningposition 2 may be greater than that at the listening position 1. Amongall positions on an arc with a radius of r₁, since the acoustic routedifference between the point source A₁ and the point source A₂ to thelistening position 3 may be the longest, compared with the listeningposition 1 and the listening position 2, the listening position 3 mayhave the highest volume of the sound heard by the user. For thelistening position 4, the distance between the listening position 4 andthe point source A₁ may be short. The sound amplitude of the pointsource A₁ at the listening position 4 may be relatively large, thevolume of the sound heard by the user at the listening position 4 may berelatively large. In summary, the volume of the sound heard by the userat the near-field listening position may change with the listeningposition and the relative position of the two point sources. When thelistening position is on the connection line between two point sourcesand on the same side of the two point sources (for example, listeningposition 3), the acoustic route difference between the two point sourcesat the listening position may be the largest (the acoustic routedifference may be the distance d between the two point sources). In thiscase (i.e., when the auricle is not used as a baffle), the volume of thesound heard by the user at this listening position may be greater thanthat at other positions. According to Equation(4), when the far-fieldsound leakage is constant, the sound leakage index corresponding to thelistening position may be the smallest, and the leakage reductioncapability may be the strongest. At the same time, reducing the distancer₁ between the listening position (for example, listening position 4)and the point source A₁ may further increase the volume at the listeningposition, reduce the sound leakage index, and improve the capability toreduce leakage.

FIG. 23 is a graph illustrating frequency response curves of two pointsources with a baffle (as shown in FIG. 20 ) at different listeningpositions in a near field according to some embodiments of the presentdisclosure. FIG. 24 is a graph illustrating=sound leakage indexes atdifferent listening positions obtained based on Equation (4) on thebasis of FIG. 23 . As shown in FIGS. 22 and 23 , compared to the casewithout a baffle, the volume of the sound generated by the two pointsources at listening position 1 may increase significantly when there isa baffle, the volume of the sound heard by the user at the listeningposition 1 may exceed that at the listening position 2 and the listeningposition 3. The reason may be that the acoustic route from the pointsource A₂ to the listening position 1 may increase after a baffle is setbetween the two point sources. As a result, the acoustic routedifference from the two point sources to the listening position 1 mayincrease significantly. The amplitude difference between the soundsgenerated by the two point sources at the listening position 1 mayincrease, which reduces the interference and cancellation of sounds,thereby increasing the volume of the sound heard by the user generatedat the listening position 1 significantly. At the listening position 4,since the distance between the listening position and the point sourceA₁ is further reduced, the sound amplitude of the point source A₁ atthis position may be larger. The volume of the sound heard by the userat the listening position 4 may still be the largest among the fourlistening positions. For listening position 2 and listening position 3,since the increased effect of the baffle on the acoustic route from thepoint source A₂ to the two listening positions is not very obvious, thevolume increase effect at the listening position 2 and the listeningposition 3 may be less than that at the listening position 1 and thelistening position 4 which are closer to the baffle.

The volume of the leaked sound in the far field may not change withlistening positions, and the volume of the sound heard by the user atthe listening position in the near field may change with listeningpositions. In this case, according to Equation (4), the leakage index ofthe acoustic output apparatus may vary in different listening positions.A listening position with a large volume of the sound heard by the user(for example, listening position 1 and listening position 4) may have asmall sound leakage index, and a strong capability to reduce leakage. Alistening position with a low volume of the sound heard by the user (forexample, listening position 2 and listening position 3), may have alarge sound leakage index, and a weak capability to reduce leakage.

Therefore, according to the actual application scenario of the acousticoutput apparatus, the user's auricle may serve as a baffle. In thiscase, the two sound guiding holes on the acoustic output apparatus maybe arranged on the front side and the rear side of the auricle,respectively, and the ear canal may be located between the two soundguiding holes as a listening position. In some embodiments, by designingthe positions of the two sound guiding holes on the acoustic outputapparatus, the distance between the sound guiding hole on the front sideof the auricle and the ear canal may be smaller than the distancebetween the sound guiding hole on the rear side of the auricle and theear canal. In this case, the acoustic output apparatus may produce alarge sound amplitude at the ear canal since the sound guiding hole onthe front side of the auricle is close to the ear canal. The soundamplitude formed by the sound guiding hole on the back of the auriclemay be smaller at the ear canal, which may avoid the interferencecancellation of the sound at the two sound guiding holes at the earcanal, thereby ensuring that the volume of the sound heard by the userat the ear canal is large. In some embodiments, the acoustic outputapparatus may include one or more contact points (e.g., “an inflectionpoint” on a supporting structure to match the shape of the ear) that cancontact with the auricle when it is worn. The contact point(s) may belocated on a connection line between the two sound guiding holes or onone side of the connection line between the two sound guiding holes. Aratio of the distance between the front sound guiding hole and thecontact point(s) to the distance between the rear sound guiding hole andthe contact point(s) may be 0.05-1. In some embodiments, the ratio maybe 0.1-1. In some embodiments, the ratio may be 0.2-1. In someembodiments, the ratio may be 0.4-1.

In some embodiments, by designing the position of the baffle on theacoustic output apparatus, a distance from a sound guiding hole locatedon the same side of the baffle as the listening position (for example,the user's ear hole) to the listening position may be less than adistance from a sound guiding hole located on the other side of thebaffle to the listening position. In such cases, since the sound guidinghole located on the same side of the baffle as the listening position isclose to the listening position, an amplitude of a sound output by thesound guiding hole located on the same side of the baffle as thelistening position may be large at the listening position, and anamplitude of a sound output by the sound guiding hole located on theother side of the baffle may be small at the listening position, whichreduce the interference and cancellation of the sounds output by twosound guiding holes at the listening position, thereby ensuring that thevolume of the sound heard by the user at the listening position islarge.

In some embodiments, when the distance from one of the two sound guidingholes to the baffle is much less than the distance from the other of thetwo sound guiding holes to the baffle, the acoustic output apparatus mayhave a large volume at the listening position in the near field. In someembodiments, a ratio of the distance from one of the two sound guidingholes to the baffle to the distance from the other of the two soundguiding holes to the baffle may be less than or equal to ⅔. Preferably,the ratio of the distance from one of the two sound guiding holes to thebaffle to the distance from the other of the two sound guiding holes tothe baffle may be less than or equal to ½. More preferably, the ratio ofthe distance from one of the two sound guiding holes to the baffle tothe distance from the other of the two sound guiding holes to the bafflemay be less than or equal to ⅓. More preferably, the ratio of thedistance from one of the two sound guiding holes to the baffle to thedistance from the other of the two sound guiding holes to the baffle maybe less than or equal to ¼. More preferably, the ratio of the distancefrom one of the two sound guiding holes to the baffle to the distancefrom the other of the two sound guiding holes to the baffle may be lessthan or equal to ⅙. More preferably, the ratio of the distance from oneof the two sound guiding holes to the baffle to the distance from theother of the two sound guiding holes to the baffle may be less than orequal to 1/10.

In some embodiments, the two sound guiding holes of the acoustic outputapparatus may be located on the same side of the listening position.Merely by way of example, the two sound guiding holes of the acousticoutput apparatus may be located below the listening position (e.g., theear hole of the user). As another example, the two sound guiding holesof the acoustic output apparatus may be located in front of thelistening position. It should be noted that the two sound guiding holesof the acoustic output apparatus are not limited to be located below andin front of the listening position. The two sound guiding holes may alsobe located above the listening position. In other embodiments, the twosound guiding holes of the acoustic output apparatus may not be limitedto being set vertically and horizontally. The two sound guide holes ofthe acoustic output apparatus may also be set obliquely. In addition,the listening position may be located on the connection line between thetwo sound guiding holes or not on the connection line between the twosound guiding holes. For example, the listening position may be locatedon the upper, lower, left, or right side of the connection line betweenthe two sound guiding holes.

When the two sound guiding holes of the acoustic output apparatus arelocated on one side of the listening position and the distance betweenthe two sound guiding holes is constant, the sound guiding hole closerto the listening position may output sound with a larger amplitude atthe listening position, and the sound guiding hole on the other side ofthe baffle may output sound with a smaller amplitude at the listeningposition, which may reduce the interference and cancellation of thesounds output by the two sound guiding holes, thereby ensuring that thevolume of the sound heard by the user at the listening position islarge. In some embodiments, a ratio of the distance between the soundguiding hole closer to the listening position and the listening positionto the distance between the two sound guiding holes may be less than orequal to 3. Preferably, the ratio of the distance between the soundguiding hole closer to the listening position and the listening positionto the distance between the two sound guiding holes may be less than orequal to 1. More preferably, the ratio of the distance between the soundguiding hole closer to the listening position and the listening positionto the distance between the two sound guiding holes may be less than orequal to 0.9. More preferably, the ratio of the distance between thesound guiding hole closer to the listening position and the listeningposition to the distance between the two sound guiding holes may be lessthan or equal to 0.6. More preferably, the ratio of the distance betweenthe sound guiding hole closer to the listening position and thelistening position to the distance between the two sound guiding holesmay be less than or equal to 0.3.

FIG. 25 is a diagram illustrating an exemplary configuration of twopoint sources and a baffle according to some embodiments of the presentdisclosure. In some embodiments, a position of the baffle between thetwo sound guiding holes may also have a certain influence on the soundoutput effect. Merely by way of example, as shown in FIG. 25 , a bafflemay be provided between a point source A₁ and a point source A₂. Thelistening position (for example, the user's ear hole) may be located onthe connection line between the point source A₁ and the point source A₂,and the listening position may be between the point source A₁ and thebaffle. A distance between the point source A₁ and the baffle may be L.A distance between the point source A₁ and the point source A₂ may be d.A distance between the point source A₁ and the listening position may beL₁, and a distance between the listening position and the baffle may beL₂. A height of the baffle in a direction perpendicular to theconnection line between the two point sources may be h. A distance froma center of the baffle to the connection line between the two pointsources may be H. When the distance L₁ between the listening positionand the point source A₁ is constant, a position of the baffle may bemoved, so that the distance L between the point source A₁ and the baffleand the distance d between the two point sources may have differentproportional relationships. A volume of the sound heard by the user atthe listening position and a volume of the far-field leakage under thedifferent proportional relationships may be obtained.

FIG. 26 is a graph illustrating frequency response curves of two pointsources without a baffle or with baffles at different positions in anear field according to some embodiments of the present disclosure. FIG.27 is a graph illustrating frequency response curves of two pointsources without a baffle or with baffles at different positions in a farfield according to some embodiments of the present disclosure. FIG. 28is a graph illustrating sound leakage indexes of two point sourceswithout a baffle or with baffles at different positions according tosome embodiments of the present disclosure. According to FIGS. 25-28 ,the volume of the far-field leakage may vary little with the change ofthe position of the baffle between the two point sources. In a situationthat the distance d between the point source A₁ and the point source A₂remains constant, when L decreases, the volume at the listening positionmay increase, the leakage index may decrease, and the capability toreduce sound leakage may be enhanced. In the same situation, when Lincreases, the volume at the listening position may increase, theleakage index may increase, and the capability to reduce sound leakagemay be weakened. A reason for the above result may be that when L issmall, the listening position may be close to the baffle, an acousticroute of the sound wave from the point source A₂ to the listeningposition may be increased due to the baffle. In this case, an acousticroute difference between the point source A₁ and the point source A₂ tothe listening position may be increased and the interferencecancellation of the sound may be reduced. As a result, the volume at thelistening position may be increased after the baffle is added. When L islarge, the listening position may be far away from the baffle. Thebaffle may have a small effect on the acoustic route difference betweenthe point source A₁ and the point source A₂ to the listening position.As a result, a volume change at the listening position may be smallafter the baffle is added.

As described above, by designing positions of the sound guiding holes onthe acoustic output apparatus, the baffle (or an auricle of a humanbody) may separate different sound guiding holes when the user wears theacoustic output apparatus, such that a structure of the acoustic outputapparatus may be simplified and the output effect of the acoustic outputapparatus may be further improved.

In some embodiments, the position of the two sound guiding holes may bedesigned so that when the user wears the acoustic output apparatus, aratio of a distance between the sound guiding hole on the front side ofthe auricle and the auricle (or a contact point on the acoustic outputapparatus for contacting with the auricle) to a distance between the twosound guiding holes may be less than or equal to 0.5. Preferably, theratio of the distance between the sound guiding hole on the front sideof the auricle and the auricle (or the contact point on the acousticoutput apparatus for contacting with the auricle) to the distancebetween the two sound guiding holes may be less than or equal to 0.3.More preferably, the ratio of the distance between the sound guidinghole on the front side of the auricle and the auricle (or the contactpoint on the acoustic output apparatus for contacting with the auricle)to the distance between the two sound guiding holes may be less than orequal to 0.1.

In some embodiments, the positions of the two sound guiding holes may bedesigned so that when the user wears the acoustic output apparatus, aratio of a distance between a sound guiding hole near the listeningposition (e.g., an entrance position of an ear canal of a human body)and the baffle to the distance between the two sound guiding holes maybe less than or equal to 0.5. Preferably, the ratio of the distancebetween the sound guiding hole near the listening position and thebaffle to the distance between the two sound guiding holes may be lessthan or equal to 0.3.

It should be noted that an acoustic route from an acoustic driver to asound guiding hole in the acoustic output apparatus may have a certaineffect on the volumes of the near-field sound and far-field soundleakage. The acoustic route may be changed by adjusting a cavity lengthbetween a vibration diaphragm in the acoustic output apparatus and thesound guiding hole. In some embodiments, the acoustic driver may includea vibration diaphragm. The front and rear sides of the vibrationdiaphragm may be coupled to two sound guiding holes through a frontchamber and a rear chamber, respectively. The acoustic routes from thevibration diaphragm to the two sound guiding holes may be different. Insome embodiments, a ratio of a first length to a second length may be0.5-2, wherein the first length is the length of the acoustic routebetween the vibration diaphragm and one of the two sound guiding holes,and the second length is the length of the acoustic route between thevibration diaphragm and the other one of the two sound guiding holes.Preferably, the ratio of the first length to the second length may be0.6-1.5. More preferably, the ratio of the first length to the secondlength may be 0.8-1.2. In other embodiments, when the acoustic outputapparatus includes a plurality of acoustic drivers, an acoustic routefrom each acoustic driver to a sound guiding hole may be adjusted bychanging a length of a cavity from an output end of the acoustic driverto the sound guiding hole. Merely by way of example, the acoustic outputapparatus may include a first acoustic driver and a second acousticdriver, and the two sound guiding holes may include a first soundguiding hole and a second sound guiding hole. The first acoustic driverand the second acoustic driver may be coupled to two sound guiding holesthrough a first cavity and a second cavity, respectively. A firstacoustic route from an output end of the first acoustic driver to thefirst sound guiding hole may be different from a second acoustic routefrom an output end of the second acoustic driver to the second soundguiding hole. A ratio of the length of the first acoustic route to thelength of the second acoustic route may be 0.5-2. Preferably, the ratioof the length of the first acoustic route to the length of the secondacoustic route may be 0.6-1.5. More preferably, the ratio of the lengthof the first acoustic route to the length of the second acoustic routemay be 0.8-1.2.

In some embodiments, on the premise of keeping the phases of the soundsgenerated at the two sound guiding holes opposite, the amplitudes of thesounds generated at the two sound guiding holes may be changed toimprove the output effect of the acoustic output apparatus.Specifically, impedances of acoustic routes connecting the acousticdriver and the two sound guiding holes may be adjusted so as to adjustthe sound amplitude at each of the two sound guiding holes. In someembodiments of this specification, the impedance may refer to aresistance that a medium needs to overcome during displacement whenacoustic waves are transmitted. The acoustic routes may or may not befilled with a damping material (e.g., a tuning net, a tuning cotton,etc.) so as to adjust the sound amplitude. For example, a resonancecavity, a sound hole, a sound slit, a tuning net, and/or a tuning cottonmay be disposed in an acoustic route so as to adjust the acousticresistance of the acoustic route, thereby changing the impedances of theacoustic route. As another example, in some embodiments, an aperture ofeach of the two sound guiding holes may be adjusted to change theacoustic resistance of the acoustic routes corresponding to the twosound guiding holes. In some embodiments, a ratio of the acousticimpedance of the acoustic route between the acoustic driver (thevibration diaphragm) and one of the two sound guiding holes to theacoustic impedance of the acoustic route between the acoustic driver andthe other sound guiding hole may be 0.5-2. Preferably, the ratio of theacoustic impedance of the acoustic route between the acoustic driver(the vibration diaphragm) and one of the two sound guiding holes to theacoustic impedance of the acoustic route between the acoustic driver andthe other sound guiding hole may be 0.8-1.2.

In some embodiments, a size of the baffle may affect the sound outputeffect of the two point sources.

FIG. 29 is a graph illustrating near-field frequency response curves oftwo point sources without a baffle or with baffles of different heightsaccording to some embodiments in FIG. 25 . As shown in FIG. 29 , at thelistening position in the near field, a volume of the near-field soundwhen baffles of different heights (that is, “h/d” shown in FIG. 29 ) areset between the two point sources may be greater than a volume of thenear-field sound when no baffle (that is, “without baffle” shown in FIG.29 ) between the two sound guiding holes. Further, as the height of thebaffle increases, that is, a ratio of the height of the baffle to thedistance between the two point sources increases, the volume provided bythe two point sources at the listening position (i.e., the near-fieldsound) may gradually increase. It may be concluded that an appropriateincrease in the height of the baffle may effectively increase the volumeat the listening position.

FIG. 30 is a graph illustrating far-field frequency response curves oftwo point sources without a baffle or with baffles of different heightsaccording to some embodiments in FIG. 25 . As shown in FIG. 30 , in thefar field (for example, positions in the environmental far away from theuser's ear), when the ratio h/d of the height of the baffle to thedistance between the two point sources changes within a certain range(for example, as shown in FIG. 30 , h/d is equal to 0.2, 0.6, 1.0, 1.4,1.8), a volume of the leaked sound generated by the two point sourcesmay be similar to a volume of the leaked sound generated by the twopoint sources without a baffle. When the ratio h/d of the height of thebaffle to the distance between the two point sources increases to acertain amount (for example, h/d is equal to 5.0), the volume of theleaked sound generated by the two point sources at the far field may belarger than the volume of the leaked sound generated by the two pointsources without a baffle. Therefore, in order to avoid a larger soundleakage in the far field, the size of the baffle between the two pointsources should not be too large.

FIG. 31 is a graph illustrating sound leakage indexes of two pointsources without a baffle or with baffles of different heights accordingto some embodiments in FIG. 25 . As shown in FIG. 31 , the sound leakageindexes when the baffles of different heights are set between the twopoint sources may be smaller than the sound leakage indexes when nobaffle is set between the two point sources. Therefore, in someembodiments, in order to keep the sound output by the acoustic outputapparatus as loud as possible in the near field and suppress the soundleakage in the far field, a baffle may be set between the two soundguiding holes, and a ratio of the height of the baffle to the distancebetween the two sound guiding holes may be less than or equal to 5.Preferably, the ratio of the height of the baffle to the distancebetween the two sound guiding holes may be less than or equal to 3. Morepreferably, the ratio of the height of the baffle to the distancebetween the two sound guiding holes may be less than or equal to 2. Morepreferably, the ratio of the height of the baffle to the distancebetween the two sound guiding holes may be less than or equal to 1.8.More preferably, the ratio of the height of the baffle to the distancebetween the two sound guiding holes may be less than or equal to 1.5.

In some embodiments, when an auricle of the human body is used as thebaffle of the acoustic output apparatus, a ratio of a height of theauricle to the distance between the two sound guiding holes may be lessthan or equal to 5. Preferably, the ratio of the height of the auricleto the distance between the two sound guiding holes may be less than orequal to 4. More preferably, the ratio of the height of the auricle tothe distance between the two sound guiding holes may be less than orequal to 3. More preferably, the ratio of the height of the auricle tothe distance between the two sound guiding holes may be less than orequal to 2. More preferably, the ratio of the height of the auricle tothe distance between the two sound guiding holes may be less than orequal to 1.8. More preferably, the ratio of the height of the auricle tothe distance between the two sound guiding holes may be less than orequal to 1.5. In some embodiments of the present disclosure, the heightof the auricle may refer to a length of the auricle along a directionperpendicular to a sagittal plane.

When the listening position and the positions of the two point sourcesare fixed, a distance between a center of the baffle and the connectionline between the two point sources may affect the volume of thenear-field sound and the volume of far-field leakage of the acousticoutput apparatus. According to FIG. 25 , the height of the baffle may beexpressed as h, and the distance from the center of the baffle to theconnection line between the two point sources may be expressed as H.When the distance d between the two point sources remains unchanged, thedistance H from the center of the baffle to the connection line betweenthe two point sources is changed, such that the distance H from thecenter of the baffle to the connection line between the two pointsources and the height h of the baffle may have different proportionalrelationships. Further, volumes of sounds at the listening position andvolumes of far-field leakage under the different proportionalrelationships may be obtained. In some embodiments, the center of thebaffle may refer to a midpoint along a height direction of the baffle(i.e., a midpoint of a length of the baffle along a directionperpendicular to the connection line between the two point sources). Itshould be noted that the baffle is not limited to the baffle with theintersection of the baffle and the connection line between the two pointsources as shown in FIG. 25 . The baffle may also be located above orbelow the connection line between the two point sources as a whole.

FIG. 32 is a graph illustrating near-field frequency response curves oftwo point sources with different ratios of a distance between a centerof a baffle and a connection line between the two point sources to aheight of the baffle according to some embodiments in FIG. 25 . As shownin FIG. 32 , the volume of sound at the listening position in the nearfield when the baffles with different positions are set between the twopoint sources (that is, “H/h” shown in FIG. 32 ) may be greater thanthat when no baffle is set between the two point sources (that is,“without baffle” in FIG. 32 ). Further, as the distance from the centerof the baffle to the connection line between the two point sourcesgradually increases, the volume of sound at the listening position inthe near field may gradually decrease. The reason may be that when thecenter of the baffle is far away from the connection line between thetwo point sources, the barrier effect of the baffle on the sounds fromthe two point sources to the listening position may be weakened. As aresult, the degree of interference and cancellation of the sounds of thetwo point sources at the listening position may become larger, whichresults in a decrease in the volume of sound at the listening position.FIG. 33 is a graph illustrating far-field frequency response curves oftwo point sources with different ratios of a distance between a centerof a baffle and a connection line between the two point sources to aheight of the baffle according to some embodiments in FIG. 25 . In thefar field, the volume of the leaked sound when the baffles withdifferent positions are set between the two point sources may be similarto that when no baffle is set between the two point sources. FIG. 34 isa graph illustrating sound leakage indexes of two point sources withdifferent ratios of a distance between a center of a baffle and aconnection line between the two point sources to a height of the baffleaccording to some embodiments in FIG. 25 . As shown in FIG. 34 , thesound leakage indexes when the baffles with different positions (thatis, different “H/h” shown in FIG. 34 ) are set between the two pointsources may be less than that when no baffle (that is, “without baffle”shown in FIG. 34 ) is set between the two point sources, which mayindicate that the ability to reduce the sound leakage is stronger whenthe baffles with different positions are set between the two pointsources. Further, as the center of the baffle gradually approaches, thatis, as the distance between the center of the baffle and the connectionline between the two point sources gradually decreases, the soundleakage indexes may gradually decrease, that is the ability to reducethe sound leakage is gradually enhanced. In some embodiments, in orderto keep the sound output by the acoustic output apparatus as loud aspossible in the near field and suppress the sound leakage in the farfield, a ratio of the distance between the center of the baffle and theconnection line between the two sound guiding holes to the height of thebaffle may be less than or equal to 2. Preferably, the ratio of thedistance between the center of the baffle and the connection linebetween the two sound guiding holes to the height of the baffle may beless than or equal to 1.5. More preferably, the ratio of the distancebetween the center of the baffle and the connection line between the twosound guiding holes to the height of the baffle may be less than orequal to 1. More preferably, the ratio of the distance between thecenter of the baffle and the connection line between the two soundguiding holes to the height of the baffle may be less than or equal to0.5. More preferably, the ratio of the distance between the center ofthe baffle and the connection line between the two sound guiding holesto the height of the baffle may be less than or equal to 0.3.

In some embodiments, the supporting structure of the acoustic outputapparatus may function as a baffle. For example, one of the two soundguiding holes may be provided on a side of the supporting structurefacing the user's ear, and the opening direction of that sound guidinghole may be toward the user's ear. The other of the two sound guidingholes may be provided on a side of the supporting structure away fromthe user's ear, and the opening direction of that sound guiding hole maybe away from the user's ear. In such cases, a distance from a structurecenter (e.g., a center of mass or a center of a shape of the supportingstructure) of the supporting structure to the connection line betweenthe two sound guiding holes may affect the volume of the near-fieldsound and the volume of the far-field leakage of the acoustic outputapparatus. As used herein, the structure center of the supportingstructure may refer to a center of the supporting structure in adirection perpendicular to the connection line between the two soundguiding holes. For the convenience of description, as shown in FIG. 35 ,the two sound guiding holes of the acoustic output apparatus may belocated at two ends of the supporting structure (“+” may indicate thesound generated by the sound guiding hole facing away from the ear, and“−” may indicate the sound generated by the sound guiding hole facingtowards the ear). The distance between the structural center of thesupporting structure and the connection line between the two soundguiding holes may be expressed as H, and a height of the supportingstructure may be expressed as h. In some embodiments, a ratio of thedistance between the structural center of the supporting structure andthe connection line between the two sound guiding holes to the height ofthe baffle (i.e., the supporting structure) may be less than or equal to2. Preferably, the ratio of the distance between the structural centerof the supporting structure and the connection line between the twosound guiding holes to the height of the baffle (i.e., the supportingstructure) may be less than or equal to 1.5. More preferably, the ratioof the distance between the structural center of the supportingstructure and the connection line between the two sound guiding holes tothe height of the baffle (i.e., the supporting structure) may be lessthan or equal to 1. More preferably, the ratio of the distance betweenthe structural center of the supporting structure and the connectionline between the two sound guiding holes to the height of the baffle(i.e., the supporting structure) may be less than or equal to 0.5. Morepreferably, the ratio of the distance between the structural center ofthe supporting structure and the connection line between the two soundguiding holes to the height of the baffle (i.e., the supportingstructure) may be less than or equal to 0.3.

It should be noted that the above descriptions are merely for theconvenience of description, and not intended to limit the presentdisclosure. It may be understood that, for those skilled in the art,after understanding the principle of the present disclosure, variousmodifications and changes in the forms and details may be made to theabove acoustic output apparatus without departing from this principle.In some embodiments, the two sound guiding holes of the acoustic outputapparatus in FIG. 35 may be not limited to being set vertically shown inFIG. 35 , and may also be set in other manners. For example, in someembodiments, the two sound guiding holes may also be set horizontally(for example, one of the two sound guiding holes may be located on afront side of the ear, and the other of the two sound guiding holes maybe located on a back side of the ear) or obliquely. In some embodiments,the two sound guiding holes in FIG. 35 may be not limited to beinglocated on both sides of the listening position, and may also be locatedon a same side of the listening position. For example, two sound guidingholes may be located above, below, or in front of the listeningposition. These changes are all within the protection scope of thepresent disclosure.

When the acoustic output apparatus has more than two sound guidingholes, that is, there are more than two point sources in the acousticoutput apparatus, a baffle may be provided between any two of theplurality of point sources. Through the cooperation of the plurality ofpoint sources and the plurality of baffles, the acoustic outputapparatus may achieve a better sound output effect. In some embodiments,the plurality of point sources may include at least one set of two pointsources with opposite phases. In order to further explain thecoordination of the plurality of point sources and the plurality ofbaffles in the acoustic output apparatus, a detailed description may begiven below in connection with FIG. 36 .

FIG. 36 is a schematic diagram illustrating a distribution of pointsources and baffles according to some embodiments of the presentdisclosure. As shown in (a) and (b) in FIG. 36 , the acoustic outputapparatus may include four point sources (respectively corresponding tofour sound guiding holes on the acoustic output apparatus). A pointsource A₁ and a point source A₂ may have a same phase. A point source A₃and a point source A₄ may have a same phase. The point source A₁ and thepoint source A₃ may have opposite phases. The point source A₁, the pointsource A₂, the point source A₃, and the point source A₄ may be separatedby two cross-arranged baffles or a plurality of spliced baffles. Thepoint source A₁ and the point source A₃ (or the point source A₄), andthe point source A₂ and the point source A₃ (or the point source A₄) mayrespectively form two point sources as described elsewhere in thepresent disclosure. As shown in (a) in FIG. 36 , the point source A₁ andthe point source A₃ may be arranged opposite to each other and may bearranged adjacent to the point source A₂ and the point source A₄. Asshown in (b) in FIG. 36 , the point source A₁ and the point source A₂are arranged opposite to each other, and may be arranged adjacent to thepoint source A₃ and the point source A₄. As shown in (c) FIG. 36 , theacoustic output apparatus may include three point sources (respectivelycorresponding to three sound guiding holes on the acoustic outputapparatus). A point source A₁ and a point source A₂ may have oppositephases, and the point source A₁ and a point source A₃ may have oppositephases, which may form two sets of two point sources as describedelsewhere in the present disclosure. The point source A₁, the pointsource A₂, and the point source A₃ may be separated by two intersectingbaffles. As shown in (d) in FIG. 36 , the acoustic output apparatus mayinclude three point sources (respectively corresponding to three soundguiding holes on the acoustic output apparatus). A point source A₁ and apoint source A₂ may have a same phase, and the point source A₁ and apoint source A₃ may have opposite phases. The point source A₁ and thepoint source A₃, and the point source A₂ and the point source A₃ mayrespectively form two point sources as described elsewhere in thepresent disclosure. The point source A₁, the point source A₂, and thepoint source A₃ may be separated by a V-shaped baffle.

FIG. 37 is a graph illustrating near-field and far-field frequencyresponse curves of multi-point sources with and without baffles betweenmulti-point sources according to some embodiments in FIG. 36 . As shownin FIG. 37 , in the near field, the volume of the sound heard by theuser when baffles are set between the multi-point sources (for example,the point source A₁, the point source A₂, the point source A₃, and thepoint source A₄) may be significantly greater than the volume of thesound heard by the user when no baffle is set between the multi-pointsources, which may indicate that the baffles set between multi-pointsources may increase the volume of the sound heard by the user in thenear field. In the far field, the volume of the leaked sound when thebaffles are set between the multi-point sources may be similar to thevolume of the leaked sound when no baffle is set between the multi-pointsources. FIG. 38 is a graph illustrating sound leakage indexes ofmulti-point sources with and without baffles between multi-pointaccording to some embodiments in FIG. 36 . As shown in FIG. 38 , on thewhole, the sound leakage indexes when the baffles are set between themulti-point sources may be significantly reduced compared to the soundleakage indexes when no baffle is set between the multi-point sources,which may indicate that the ability to reduce the sound leakage may besignificantly enhanced when the baffles are set between the multi-pointsources. FIG. 39 is a graph illustrating sound leakage indexes ofmulti-point sources corresponding to two distribution modes shown in (a)and (b) in FIG. 36 . As shown in FIG. 39 , in a specific frequencyrange, among the four point sources, the sound leakage indexes (“(b)”shown in FIG. 39 ) when two point sources (for example, the point sourceA₁ and the point source A₂, the point source A₃ and the point source A₄in (b) in FIG. 36 ) with the same phase are arranged opposite to eachother on the periphery of the baffle may be significantly smaller thanthe sound leakage indexes (“(a)” shown in FIG. 39 ) when two pointsources (for example, the point source A₁ and the point source A₃, thepoint source A₂ and the point source A₄ in (a) in FIG. 36 ) withopposite phases are arranged opposite to each other on the periphery ofthe baffle, which may indicate that the ability to reduce the soundleakage of the two point sources with the same phase arranged oppositeto each other on the periphery of the baffle or the two point sourceswith the opposite phases arranged adjacently is stronger.

According to the above contents, in some embodiments, when the acousticoutput apparatus includes a plurality of sound guiding holes, in orderto keep the sound output by the acoustic output apparatus in the nearfield as loud as possible, and suppress the sound leakage in the farfield, a baffle may be provided between any two of the plurality ofsound guiding holes, that is, any two of the plurality of sound guidingholes may be separated by the baffle. Preferably, sounds with the samephase (or approximately the same) or opposite (or approximatelyopposite) phases may be output between the plurality of sound guidingholes. More preferably, the sound guiding holes that output sounds withthe same phase may be arranged oppositely, and the sound guiding holesthat output sounds with opposite phases may be arranged adjacently.

It should be noted that the above descriptions are merely for theconvenience of description, and not intended to limit the presentdisclosure. It may be understood that, for those skilled in the art,after understanding the principle of the present disclosure, variousmodifications and changes in the forms and details of the acousticoutput apparatus may be made without departing from this principle. Forexample, a count of point sources may be not limited to the above two,three, or four, but may also be five, six, seven, or more. A specificdistribution form of the point sources and a structure and shape of thebaffle may be adjusted according to different counts of point sources.As another example, the shape of the baffle may be not limited to astraight plate shown in some figures in the present disclosure, and thebaffle may also be a curved plate with a certain curvature. Thesechanges are all within the protection scope of the present disclosure.

FIG. 40 is a schematic diagram illustrating an exemplary structure of anacoustic output apparatus according to some embodiments of the presentdisclosure.

For human ears, the frequency band of sound that can be heard may beconcentrated in a mid-low-frequency band. An optimization goal in themid-low-frequency band may be to increase a volume of the sound heard bythe user. If the listening position is fixed, parameters of the twopoint sources may be adjusted such that the volume of the sound heard bythe user may increase significantly while a volume of leaked sound maybe substantially unchanged (an increase in the volume of the sound heardby the user may be greater than an increase in the volume of the soundleakage). In a high-frequency band, a sound leakage reduction effect ofthe two point sources may be weaker. In the high-frequency band, anoptimization goal may be reducing sound leakage. The sound leakage maybe further reduced by adjusting the parameters of the two point sourcesof different frequencies. In some embodiments, the acoustic outputapparatus 100 may also include an acoustic driver 130. The acousticdriver 130 may output sounds from a pair of third sound guiding holes.Details regarding the acoustic driver 130, the third sound guidingholes, and a structure between the acoustic driver and the third soundguiding hole may be described with reference to the acoustic driver 120and the first sound guiding holes 112 and the second sound guiding holes112. In some embodiments, the acoustic driver 130 and the acousticdriver 120 may output sounds of different frequencies. In someembodiments, the acoustic output apparatus may further include acontroller configured to cause the acoustic driver 120 to output soundin the first frequency range, and cause the acoustic driver 130 tooutput sound in the second frequency range. The second frequency rangemay include frequencies higher than the first frequency range. Forexample, the first frequency range may be 100 Hz-1000 Hz, and the secondfrequency range may be 1000 Hz-10000 Hz. In some embodiments, there isan overlapping frequency range between the first frequency range and thesecond frequency range. The sounds in the overlapping frequency rangemay be regarded as being output from the first sound guiding hole, thesecond sound guiding hole, and the pair of third sound guiding holestogether.

In some embodiments, the acoustic driver 120 may be a low-frequencyspeaker, and the acoustic driver 130 may be a mid-high-frequencyspeaker. Due to different frequency response characteristics of thelow-frequency speaker and the mid-high-frequency speaker, frequencybands of the output sound may also be different. High-frequency bandsand low-frequency bands may be divided by using the low-frequencyspeakers and the mid-high-frequency speakers, and accordingly, twolow-frequency point sources and two mid-high-frequency point sources maybe constructed to perform near-field sound output and a far-fieldleakage reduction. For example, the acoustic driver 120 may provide twopoint sources for outputting low-frequency sound through the soundguiding hole 111 and the sound guiding hole 112, which may be mainlyused for outputting sound in low-frequency band. The two low-frequencypoint sources may be distributed on both sides of an auricle to increasea volume near the near-field ear. The acoustic driver 130 may providetwo point sources for outputting mid-high-frequency sound through twosecond sound guiding holes. A mid-high-frequency sound leakage may bereduced by adjusting a distance between the two second sound guidingholes. The two mid-high-frequency point sources may be distributed onboth sides of the auricle or on the same side of the auricle.Alternatively, the acoustic driver 120 may provide two point sources foroutputting full-frequency sound through the sound guiding hole 111 andthe sound guiding hole 112 so as to further increase the volume of thenear-field sound.

Further, the distance d₂ between the pair of third sound guiding holesmay be smaller than the distance d₁ between the sound guiding hole 111and the sound guiding hole 112, that is, d₁ may be greater than d₂. FIG.41 is a schematic diagram illustrating sound leakage indexes under theaction of a combination of low-frequency two point sources andhigh-frequency two point sources according to some embodiments of thepresent disclosure. As shown in FIG. 41 , by setting a set oflow-frequency two point sources and a set high-frequency two pointsources with different distances, a stronger ability to reduce soundleakage may be achieved compared with a single point source. In thelow-frequency range, when the distance (d1) between the low-frequencytwo point sources is adjusted (e.g., increased), the increase in thevolume of the near-field sound may be greater than the increase in thevolume of the far-field leakage, which may achieve a higher volume ofthe near-field sound output in the low-frequency band. At the same time,in the low-frequency range, because that the sound leakage of the lowfrequency two point sources is very small, adjusting (increasing) thedistance d1 may slightly increase the sound leakage, but the increasedsound leakage is still be kept at a low level (α value is even furtherreduced). In the high-frequency range, by adjusting (e.g., reducing) thedistance (d2) between the high frequency two point sources, the problemthat the cutoff frequency of high-frequency sound leakage reduction istoo low and the frequency band of the sound leakage reduction is toonarrow may be overcome. Therefore, a stronger effect of sound leakagereduction may be achieved in higher frequency bands, which may meet theneeds of open acoustic output apparatus.

It should be noted that a curve of a total leaked sound shown in FIG. 41is an ideal, which is only used to illustrate the principle and effect.Affected by factors such as the filter characteristic of a circuit, thefrequency characteristic of a transducer, and the frequencycharacteristic of an acoustic route, the actual low-frequency andhigh-frequency sounds output by the acoustic output apparatus may differfrom those shown in FIG. 41 . In addition, low-frequency andhigh-frequency sounds may have a certain overlap (aliasing) in thefrequency band near the frequency division point, causing the totalleaked sound of the acoustic output apparatus does not have a mutationat the frequency division point as shown in FIG. 41 . Instead, there maybe a gradient and/or a transition in the frequency band near thefrequency division point, as shown by a thin solid line in FIG. 41 .

In some embodiments, the pair of third sound guiding holes may outputsounds with a phase difference. Preferably, the third sound guidingholes may output sounds with opposite phases. In some embodiments, theacoustic driver 130 that output sounds with a phase difference from thethird sound guiding holes may be similar to the acoustic driver 120 thatoutputting sounds from the sound guiding holes as described elsewhere inthis disclosure.

It should be noted that the descriptions of the present disclosure maynot limit an actual use scenario of the acoustic output apparatus. Theacoustic output apparatus may be any apparatus outputting the sound or aportion thereof. For example, the acoustic output apparatus may beapplied to a phone. FIG. 42 is a schematic diagram illustrating a phonehaving sound guiding holes according to some embodiments of the presentdisclosure. As shown in FIG. 42 , a plurality of sound guiding holes asdescribed elsewhere in the present disclosure may be arranged on a top4220 (that is, an upper end perpendicular to a display of the phone4200) of a phone 4200. Merely by way of example, sound guiding holes4201 may constitute a set of two point sources (or an array of pointsources) for outputting sounds. A first sound guiding hole of the soundguiding holes 4201 may be close to a left end of the top 4220, and asecond sound guiding hole of the sound guiding holes 4201 may be closeto a right end of the top 4220. The two sound guiding holes may beseparated by a certain distance. An acoustic driver 4230 may be providedinside a housing of the phone 4200. The sounds generated by the acousticdriver 4230 may be transmitted outward through the sound guiding holes4201.

In some embodiments, the two sound guiding holes 4201 may output a setof sounds with the opposite (or approximately the opposite) phase andthe same (or approximately the same) amplitude. When a user places thephone near an ear to receive voice information, the sound guiding holes4201 may be located on both sides of a user's ear, according to thedescriptions of other embodiments in the present disclosure, which maybe equivalent to increasing an acoustic distance of the sound from thesound guiding hole to the user's ear, so that the sound guiding holes4201 may output strong near-field sound to the user. Meanwhile, theuser's ear may have little effect on sounds output by the sound guidingholes in a far field, so that due to the interference and cancellationof the sounds in the far field, the sound guiding holes 4201 may reducesound leakage to the surrounding environment. In addition, by arrangingthe sound guiding holes on the top portion of the phone instead of anupper portion of the display of the phone, a space on a front of thephone may be saved. Therefore, an area of the display of the phone maybe further increased and the appearance of the phone more concise andbeautiful.

It should be understood that the above descriptions of the sound guidingholes on the phone are merely for illustration purposes. Those skilledin the art may make various modifications to the above structureswithout departing this principle. The modified structures may be withinthe protection scope of the present disclosure. For example, all or aportion of the sound guiding holes 4201 may also be set at otherpositions of the phone 4200, which may still ensure that the user mayhear a relatively loud volume when receiving voice information whileavoiding leakage of the voice information to the surroundingenvironment. For example, the first sound guiding hole may be arrangedon the top 4220 (relatively close to the user's ear), and the secondsound guiding hole may be arranged on a back or a side of the phone 4200(relatively away from the user's ear). When the user places the firstsound guiding hole near the ear to receive the voice information, thehousing of the phone 4200 may be equivalent to a “baffle” that “blocks”between the second sound guiding hole and the user's ear, which may addan acoustic distance from the second sound guiding hole to the user'sear. Therefore, a volume heard by the user's ear may be increased. Asanother example, acoustic drivers that output sounds in differentfrequency ranges may be disposed inside the housing of the phone 4200,and sound guiding holes corresponding to these acoustic drivers may beprovided with or without baffles in the manner described above.

It should be noted that the above descriptions are merely for theconvenience of description, and not intended to limit the presentdisclosure. It may be understood that, for those skilled in the art,after understanding the principle of the present disclosure, variousmodifications and changes in the forms and details of the acousticoutput apparatus may be made without departing from this principle. Insome embodiments, the sound guiding hole 111 and the sound guiding hole112 corresponding to the acoustic driver 120 may not be distributed onboth sides of the auricle, and/or the two third guide holescorresponding to the acoustic driver 130 may not be distributed on thefront side of the auricle. For example, the pair of third sound guidingholes corresponding to the acoustic driver 130 may be distributed on thesame side of the auricle (for example, a rear side, an upper side, or alower side of the auricle). As another example, the pair of third soundguiding holes corresponding to the acoustic driver 130 may bedistributed on both sides of the auricle. As still another example, whenthe sound guiding hole 111, the sound guiding hole 112, and/or the pairof third sound guiding holes are located on the same side of theauricle, a baffle (e.g., a baffle 4240) may be disposed between thesound guiding holes 111 and the sound guiding hole 112, and/or betweenthe pair of third sound guiding holes to further increase the volume ofthe near-field sound and reduce the volume of the far-field leakage. Asstill another example, in some embodiments, the two sound guiding holescorresponding to the acoustic driver 120 may be located on the same sideof the auricle (for example, a front side, a rear side, an upper side,and a lower side of the auricle).

Having thus described the basic concepts, it may be rather apparent tothose skilled in the art after reading this detailed disclosure that theforegoing detailed disclosure is intended to be presented by way ofexample only and is not limiting. Various alterations, improvements, andmodifications may occur and are intended for those skilled in the art,though not expressly stated herein. These alterations, improvements, andmodifications are intended to be suggested by this disclosure and arewithin the spirit and scope of the exemplary embodiments of thisdisclosure.

Moreover, certain terminology has been used to describe embodiments ofthe present disclosure. For example, the terms “one embodiment,” “anembodiment,” and/or “some embodiments” mean that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the present disclosure.Therefore, it is emphasized and should be appreciated that two or morereferences to “an embodiment” or “one embodiment” or “an alternativeembodiment” in various portions of this specification are notnecessarily all referring to the same embodiment. Furthermore, theparticular features, structures, or characteristics may be combined assuitable in one or more embodiments of the present disclosure.

Further, it will be appreciated by one skilled in the art, aspects ofthe present disclosure may be illustrated and described herein in any ofa number of patentable classes or context including any new and usefulprocess, machine, manufacture, or composition of matter, or any new anduseful improvement thereof. Accordingly, aspects of the presentdisclosure may be implemented entirely hardware, entirely software(including firmware, resident software, micro-code, etc.) or combiningsoftware and hardware implementation that may all generally be referredto herein as a “unit,” “module,” or “system.” Furthermore, aspects ofthe present disclosure may take the form of a computer program productembodied in one or more computer-readable media having computer-readableprogram code embodied thereon.

A non-transitory computer-readable signal medium may include apropagated data signal with computer readable program code embodiedtherein, for example, in baseband or as part of a carrier wave. Such apropagated signal may take any of a variety of forms, includingelectromagnetic, optical, or the like, or any suitable combinationthereof. A computer-readable signal medium may be any computer-readablemedium that is not a computer-readable storage medium and that maycommunicate, propagate, or transport a program for use by or inconnection with an instruction execution system, apparatus, or device.Program code embodied on a computer-readable signal medium may betransmitted using any appropriate medium, including wireless, wireline,optical fiber cable, RF, or the like, or any suitable combination of theforegoing.

Computer program code for carrying out operations for aspects of thepresent disclosure may be written in any combination of one or moreprogramming languages, including an object-oriented programming languagesuch as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB. NET,Python or the like, conventional procedural programming languages, suchas the “C” programming language, Visual Basic, Fortran, Perl, COBOL,PHP, ABAP, dynamic programming languages such as Python, Ruby, andGroovy, or other programming languages. The program code may executeentirely on the user's computer, partly on the user's computer, as astand-alone software package, partly on the user's computer and partlyon a remote computer, or entirely on the remote computer or server. Inthe latter scenario, the remote computer may be connected to the user'scomputer through any type of network, including a local area network(LAN) or a wide area network (WAN), or the connection may be made to anexternal computer (for example, through the Internet using an InternetService Provider) or in a cloud computing environment or offered as aservice such as a Software as a Service (SaaS).

Furthermore, the recited order of processing elements or sequences, orthe use of numbers, letters, or other designations, therefore, is notintended to limit the claimed processes and methods to any order exceptas may be specified in the claims. Although the above disclosurediscusses through various examples what is currently considered to be avariety of useful embodiments of the disclosure, it is to be understoodthat such detail is solely for that purpose and that the appended claimsare not limited to the disclosed embodiments, but, on the contrary, areintended to cover modifications and equivalent arrangements that arewithin the spirit and scope of the disclosed embodiments. For example,although the implementation of various components described above may beembodied in a hardware device, it may also be implemented as asoftware-only solution, e.g., an installation on an existing server ormobile device.

Similarly, it should be appreciated that in the foregoing description ofembodiments of the present disclosure, various features are sometimesgrouped together in a single embodiment, figure, or description thereofto streamline the disclosure aiding in the understanding of one or moreof the various inventive embodiments. This method of disclosure,however, is not to be interpreted as reflecting an intention that theclaimed object matter requires more features than are expressly recitedin each claim. Rather, inventive embodiments lie in less than allfeatures of a single foregoing disclosed embodiment.

In some embodiments, the numbers expressing quantities, properties, andso forth, used to describe and claim certain embodiments of theapplication are to be understood as being modified in some instances bythe term “about,” “approximate,” or “substantially.” For example,“about,” “approximate” or “substantially” may indicate ±20% variation ofthe value it describes, unless otherwise stated. Accordingly, in someembodiments, the numerical parameters set forth in the writtendescription and attached claims are approximations that may varydepending upon the desired properties sought to be obtained by aparticular embodiment. In some embodiments, the numerical parametersshould be construed in light of the number of reported significantdigits and by applying ordinary rounding techniques. Notwithstandingthat the numerical ranges and parameters setting forth the broad scopeof some embodiments of the application are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspracticable.

Each of the patents, patent applications, publications of patentapplications, and other material, such as articles, books,specifications, publications, documents, things, and/or the like,referenced herein is hereby incorporated herein by this reference in itsentirety for all purposes, excepting any prosecution file historyassociated with same, any of same that is inconsistent with or inconflict with the present document, or any of same that may have alimiting effect as to the broadest scope of the claims now or laterassociated with the present document. By way of example, should there beany inconsistency or conflict between the description, definition,and/or the use of a term associated with any of the incorporatedmaterial and that associated with the present document, the description,definition, and/or the use of the term in the present document shallprevail.

In closing, it is to be understood that the embodiments of theapplication disclosed herein are illustrative of the principles of theembodiments of the application. Other modifications that may be employedmay be within the scope of the application. Thus, by way of example, butnot of limitation, alternative configurations of the embodiments of theapplication may be utilized in accordance with the teachings herein.Accordingly, embodiments of the present application are not limited tothat precisely as shown and described.

We claim:
 1. An acoustic output apparatus, comprising: at least oneacoustic driver configured to output sounds with opposite phases throughat least two sound guiding holes, the at least two sound guiding holesincluding a first sound guiding hole and a second sound guiding hole;and a supporting structure, the supporting structure being configured tosupport the at least one acoustic driver, both the supporting structureand the acoustic driver approach but not block a user's ear canal,wherein: the at least one acoustic driver includes a vibrationdiaphragm, a first acoustic route from the vibration diaphragm to thefirst sound guiding hole is different from a second acoustic route fromthe vibration diaphragm to the second sound guiding hole.
 2. Theacoustic output apparatus of claim 1, wherein the at least one acousticdriver includes a vibration diaphragm, a first side of the vibrationdiaphragm in the supporting structure is provided with a first chamberfor transmitting sound, the first chamber being acoustically coupledwith the first sound guiding hole, and a second side of the vibrationdiaphragm in the supporting structure is provided with a second chamberfor transmitting sound, the second chamber being acoustically coupledwith the second sound guiding hole.
 3. The acoustic output apparatus ofclaim 1, wherein a ratio of a length of the first acoustic route to alength of the second acoustic route is 0.5-2.
 4. The acoustic outputapparatus of claim 1, wherein the sounds output from the first andsecond sound guiding holes have different sound pressure amplitudes. 5.The acoustic output apparatus of claim 1, wherein the at least oneacoustic driver includes a first acoustic driver and a second acousticdriver, and a controller is configured to control the first acousticdriver to output a first sound through the first sound guiding hole andthe second acoustic driver to output a second sound from the secondsound guiding hole, the first sound and the second sound having oppositephases.
 6. The acoustic output apparatus of claim 5, wherein a firstacoustic route from the first acoustic driver to the first sound guidinghole is different from a second acoustic route from the second acousticdriver to the second sound guiding hole.
 7. The acoustic outputapparatus of claim 6, wherein a ratio of the first acoustic route fromthe first acoustic driver to the first sound guiding hole and the secondacoustic route from the second acoustic driver to the second soundguiding hole is 0.5-2.
 8. The acoustic output apparatus of claim 5,wherein the first sound and the second sound have different soundpressure amplitudes.
 9. The acoustic output apparatus of claim 1,wherein a distance between the first sound guiding hole and the secondsound guiding hole is less than or equal to 12 centimeters.
 10. Theacoustic output apparatus of claim 1, wherein the supporting structureincludes a baffle, the supporting structure the first sound guiding holeand a user's ear are located on one side of the baffle, the second soundguiding hole is located on the other side of the baffle, and a length ofan acoustic route from the first sound guiding hole to the user's ear isless than a length of an acoustic route from the second sound guidinghole to the user's ear.
 11. The acoustic output apparatus of claim 1,wherein the first and second sound guiding holes are located on a sameside of the user's ear canal, a ratio of a distance between the user'sear canal and a sound guiding hole that is closer to the user's earcanal among the first and second sound guiding holes to a distancebetween the first and second sound guiding holes is less than or equalto
 3. 12. The acoustic output apparatus of claim 1, wherein the firstand second sound guiding holes are located on a same side of the user'sear canal, a ratio of a distance between the user's ear canal and asound guiding hole that is closer to the user's ear canal among thefirst and second sound guiding holes to a distance between the first andsecond sound guiding holes is less than or equal to
 1. 13. The acousticoutput apparatus of claim 1, wherein the first and second sound guidingholes are located on a same side of the user's ear canal, a ratio of adistance between the user's ear canal and a sound guiding hole that iscloser to the user's ear canal among the first and second sound guidingholes to a distance between the first and second sound guiding holes isless than or equal to 0.9.
 14. The acoustic output apparatus of claim 1,wherein the first and second sound guiding holes are located on a sameside of the user's ear canal, a ratio of a distance between the user'sear canal and a sound guiding hole that is closer to the user's earcanal among the first and second sound guiding holes to a distancebetween the first and second sound guiding holes is less than or equalto 0.6.
 15. The acoustic output apparatus of claim 1, wherein the firstand second sound guiding holes are located on a same side of the user'sear canal, a ratio of a distance between the user's ear canal and asound guiding hole that is closer to the user's ear canal among thefirst and second sound guiding holes to a distance between the first andsecond sound guiding holes is less than or equal to 0.3.
 16. Theacoustic output apparatus of claim 1, wherein a ratio of a height of thebaffle to a distance between the first and second sound guiding holes isless than or equal to
 5. 17. The acoustic output apparatus of claim 1,wherein a ratio of a height of the baffle to a distance between thefirst and second sound guiding holes is less than or equal to
 3. 18. Theacoustic output apparatus of claim 1, wherein a ratio of a height of thebaffle to a distance between the first and second sound guiding holes isless than or equal to 1.5.
 19. The acoustic output apparatus of claim 1,wherein a ratio of a distance between a center of the baffle and aconnection line between the first and second sound guiding holes to aheight of the baffle is less than or equal to
 2. 20. The acoustic outputapparatus of claim 1, wherein the at least two sound guiding holesinclude a third sound guiding hole and a fourth sound guiding hole, anda ratio of a distance between the third sound guiding hole and thebaffle to a distance between the fourth sound guiding hole and thebaffle is less than or equal to ⅔.